OpenBSD: Failing to link custom libpng to custom libz, any thoughts how fix?

[Bob-4]

Hi,

I am trying to make a custom build of libpng in my home directory,
using a libz build that I made in my home directory also.

Both are latest version, libpng 1.6.37 same as OpenBSD's port
https://cvsweb.openbsd.org/ports/graphics/png/Makefile?rev=1.125&content-type=text/x-cvsweb-markup
and libz the latest one they published. For zlib it's 1.2.11
from http://zlib.net/ from 2017, OpenBSD does not have a port but
base bundles a 2009 version. Since 2009, significantly an export
"inflateReset2" has been added.

I'll start with the detail problem, and discuss the reproduction at the
bottom:


This has brought me to the bizarre issue that the libpng build plainly
refuses to link to my custom libz file /home/myuser/lib/libz.so.1 .
Instead, it insists with linking to the OS' global
/usr/lib/libz.so.5.0 .

/home/myuser/lib/ contains libz.so , libz.a, libz.so.1 and
libz.so.1.2.11 .

I have reduced the issue to the libpng build step where it produces
libpng.so:

/usr/local/bin/egcc -shared  -fPIC -DPIC -o .libs/libpng.so.16.37
.libs/png.o .libs/pngerror.o .libs/pngget.o .libs/pngmem.o
.libs/pngpread.o .libs/pngread.o .libs/pngrio.o .libs/pngrtran.o
.libs/pngrutil.o .libs/pngset.o .libs/pngtrans.o .libs/pngwio.o
.libs/pngwrite.o .libs/pngwtran.o .libs/pngwutil.o -L/home/myuser/lib
-lm -lz -Og -g -fstack-protector-all
[with or without: -Wl,--version-script=libpng.vers]
[with or without: -Wl,-t]

When provided with "-Wl,-t", LD run by GCC prints out:

"/usr/lib/crtbeginS.o
.libs/png.o
.libs/pngerror.o
.libs/pngget.o
.libs/pngmem.o
.libs/pngpread.o
.libs/pngread.o
.libs/pngrio.o
.libs/pngrtran.o
.libs/pngrutil.o
.libs/pngset.o
.libs/pngtrans.o
.libs/pngwio.o
.libs/pngwrite.o
.libs/pngwtran.o
.libs/pngwutil.o
/usr/lib/libm.so.10.1
/usr/lib/libz.so.5.0
/usr/lib/crtendS.o"

which shows that already at link time it picks the OS global one
(that is /usr/lib/libz.so.5.0).

What appears is that GCC ignores the "-L" search path given to it.

"readelf -d .libs/libpng.so.16.37" shows:

"Dynamic section at offset 0x40050 contains 25 entries:
  Tag               Type      Name/Value
 0x000000000000001d (RUNPATH) Library runpath: [/home/myuser/lib]
 0x0000000000000001 (NEEDED)  Shared library: [libm.so.10.1]
 0x0000000000000001 (NEEDED)  Shared library: [libz.so.5.0]"

Again providing receipt that the wrong LibZ is linked.

"objdump -p .libs/libpng.so.16.37" shows the same:

".libs/libpng.so.16.37:     file format elf64-x86-64

Program Header: ...

Dynamic Section:
  RUNPATH     /home/myuser/lib
  NEEDED      libm.so.10.1
  NEEDED      libz.so.5.0"


The way I got to this issue, was that the libpng "make" would
crash with:

"ld: error: undefined symbol: inflateReset2
>>> referenced by pngfix.c:2184 (contrib/tools/pngfix.c:2184)
>>>               contrib/tools/pngfix.o:(zlib_reset)
collect2: error: ld returned 1 exit status"

This turned out to be that the libpng build process' linking of its
"pngfix" accessory tool, would crash because inflateReset2 was not
found in the OS' libz (but it is in my custom one).

"ldd" showed that libpng.so.17.37 already linked to the OS provided
one as discussed above.

Whole console interaction leading to the crash below.


This whole experience makes me suspicious that maybe for instance
"libz" is a reserved filename where only the OS' installation is
accepted, but that would make no sense at all?

Any thoughts for how to successfully make GCC link, please let me know,

Thanks,
Bob

$ CC=/usr/local/bin/egcc \

> CXX=/usr/local/bin/eg++ \
> LD_LIBRARY_PATH=/home/myuser/lib \
> LDFLAGS="-L/home/myuser/lib -lz " \
> LIBS="-L/home/myuser/lib -I/home/myuser/include -lz " \
> CFLAGS="-Og -g -fstack-protector-all -fpic \
>         -I/home/myuser/include -L/home/myuser/lib -lz" \
> CPPFLAGS="-Og -g -fstack-protector-all -fpic \
>           -I/home/myuser/include -L/home/myuser/lib -lz " \
> ./configure \
>      --prefix=/home/myuser \
>      --enable-hardware-optimizations=no \
>      --with-pic=yes \
>      --enable-unversioned-links \
>      --with-zlib-prefix=/home/myuser/lib

checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... ./install-sh -c -d
checking for gawk... no
checking for mawk... no
checking for nawk... no
checking for awk... awk
checking whether make sets $(MAKE)... yes
checking whether make supports nested variables... yes
checking whether to enable maintainer-specific portions of Makefiles... no
checking for gcc... /usr/local/bin/egcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out
checking for suffix of executables...
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether /usr/local/bin/egcc accepts -g... yes
checking for /usr/local/bin/egcc option to accept ISO C89... none needed
checking whether /usr/local/bin/egcc understands -c and -o together... yes
checking whether make supports the include directive... yes (GNU style)
checking dependency style of /usr/local/bin/egcc... gcc3
checking dependency style of /usr/local/bin/egcc... gcc3
checking build system type... x86_64-unknown-openbsd6.7
checking host system type... x86_64-unknown-openbsd6.7
checking for a sed that does not truncate output... /usr/bin/sed
checking for grep that handles long lines and -e... /usr/bin/grep
checking for egrep... /usr/bin/grep -E
checking for fgrep... /usr/bin/grep -F
checking how to print strings... print -r
checking for ld used by /usr/local/bin/egcc... /usr/bin/ld
checking if the linker (/usr/bin/ld) is GNU ld... yes
checking how to run the C preprocessor... /usr/local/bin/egcc -E
checking for gawk... (cached) awk
checking whether ln -s works... yes
checking whether make sets $(MAKE)... (cached) yes
checking for BSD- or MS-compatible name lister (nm)... /usr/bin/nm -B
checking the name lister (/usr/bin/nm -B) interface... BSD nm
checking the maximum length of command line arguments... 393216
checking how to convert x86_64-unknown-openbsd6.7 file names to x86_64-unknown-openbsd6.7 format... func_convert_file_noop
checking how to convert x86_64-unknown-openbsd6.7 file names to toolchain format... func_convert_file_noop
checking for /usr/bin/ld option to reload object files... -r
checking for objdump... objdump
checking how to recognize dependent libraries... match_pattern /lib[^/]+(\.so\.[0-9]+\.[0-9]+|\.so|_pic\.a)$
checking for dlltool... no
checking how to associate runtime and link libraries... print -r --
checking for ar... ar
checking for archiver @FILE support... @
checking for strip... strip
checking for ranlib... ranlib
checking command to parse /usr/bin/nm -B output from /usr/local/bin/egcc object... ok
checking for sysroot... no
checking for a working dd... /bin/dd
checking how to truncate binary pipes... /bin/dd bs=4096 count=1
checking for mt... mt
checking if mt is a manifest tool... no
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking for dlfcn.h... yes
checking for objdir... .libs
checking if /usr/local/bin/egcc supports -fno-rtti -fno-exceptions... no
checking for /usr/local/bin/egcc option to produce PIC... -fPIC -DPIC
checking if /usr/local/bin/egcc PIC flag -fPIC -DPIC works... yes
checking if /usr/local/bin/egcc static flag -static works... yes
checking if /usr/local/bin/egcc supports -c -o file.o... yes
checking if /usr/local/bin/egcc supports -c -o file.o... (cached) yes
checking whether the /usr/local/bin/egcc linker (/usr/bin/ld) supports shared libraries... yes
checking whether -lc should be explicitly linked in... yes
checking dynamic linker characteristics... openbsd6.7 ld.so
checking how to hardcode library paths into programs... immediate
checking whether stripping libraries is possible... yes
checking if libtool supports shared libraries... yes
checking whether to build shared libraries... yes
checking whether to build static libraries... yes
checking that AWK works... ok
checking if we need to force back C standard to C89... no
checking for ANSI C header files... (cached) yes
checking for an ANSI C-conforming const... yes
checking for size_t... yes
checking whether struct tm is in sys/time.h or time.h... time.h
checking for C/C++ restrict keyword... __restrict
checking for working strtod... yes
checking for pow... no
checking for pow in -lm... yes
checking for clock_gettime... yes
checking for zlibVersion in -lz... yes
checking for feenableexcept in -lm... yes
checking for feenableexcept... yes
checking if using Solaris linker... no
checking if libraries can be versioned... yes
checking for symbol prefix...
configure: pkgconfig directory is ${libdir}/pkgconfig
configure: Extra options for compiler:
checking that generated files are newer than configure... done
configure: creating ./config.status
config.status: creating Makefile
config.status: creating libpng.pc
config.status: creating libpng-config
config.status: creating config.h
config.status: executing depfiles commands
config.status: executing libtool commands


$ gmake -j3 VERBOSE=1
rm -f pnglibconf.c pnglibconf.tf[45]
awk -f ./scripts/options.awk out=pnglibconf.tf4 version=search\
    ./pngconf.h ./scripts/pnglibconf.dfa\
    ./pngusr.dfa  1>&2
awk -f ./scripts/options.awk out=pnglibconf.tf5 pnglibconf.tf4 1>&2
rm pnglibconf.tf4
mv pnglibconf.tf5 pnglibconf.c
rm -f pnglibconf.out pnglibconf.tf[12]
test -d scripts || mkdir scripts || test -d scripts
/usr/local/bin/egcc -E -DHAVE_CONFIG_H -I. \
    -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz  -DPNGLIB_LIBNAME='PNG16_0' -DPNGLIB_VERSION='1.6.37' -DSYMBOL_PREFIX='' -DPNG_NO_USE_READ_MACROS -DPNG_BUILDING_SYMBOL_TABLE  pnglibconf.c > pnglibconf.tf1
awk -f "./scripts/dfn.awk" out="pnglibconf.tf2" pnglibconf.tf1 1>&2
rm -f pnglibconf.tf1
mv pnglibconf.tf2 pnglibconf.out
rm -f pnglibconf.h
cp pnglibconf.out pnglibconf.h
gmake  all-am
gmake[1]: Entering directory '/home/myuser/src/libpng'
:>pngprefix.h
rm -f scripts/vers.out scripts/vers.tf[12]
cp libpng-config libpng16-config
test -d scripts || mkdir scripts || test -d scripts
cp libpng.pc libpng16.pc
/usr/local/bin/egcc -E -DHAVE_CONFIG_H -I. \
    -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz  -DPNGLIB_LIBNAME='PNG16_0' -DPNGLIB_VERSION='1.6.37' -DSYMBOL_PREFIX='' -DPNG_NO_USE_READ_MACROS -DPNG_BUILDING_SYMBOL_TABLE  scripts/vers.c > scripts/vers.tf1
depbase=`echo pngtest.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\
/usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngtest.o -MD -MP -MF $depbase.Tpo -c -o pngtest.o pngtest.c &&\
mv -f $depbase.Tpo $depbase.Po
depbase=`echo contrib/tools/pngcp.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\
/usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT contrib/tools/pngcp.o -MD -MP -MF $depbase.Tpo -c -o contrib/tools/pngcp.o contrib/tools/pngcp.c &&\
mv -f $depbase.Tpo $depbase.Po
awk -f "./scripts/dfn.awk" out="scripts/vers.tf2" scripts/vers.tf1 1>&2
rm -f scripts/vers.tf1
mv scripts/vers.tf2 scripts/vers.out
depbase=`echo contrib/libtests/timepng.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\
/usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT contrib/libtests/timepng.o -MD -MP -MF $depbase.Tpo -c -o contrib/libtests/timepng.o contrib/libtests/timepng.c &&\
mv -f $depbase.Tpo $depbase.Po
depbase=`echo contrib/tools/pngfix.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\
/usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT contrib/tools/pngfix.o -MD -MP -MF $depbase.Tpo -c -o contrib/tools/pngfix.o contrib/tools/pngfix.c &&\
mv -f $depbase.Tpo $depbase.Po
depbase=`echo png.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/sh ./libtool  --tag=CC   --mode=compile /usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT png.lo -MD -MP -MF $depbase.Tpo -c -o png.lo png.c &&\
mv -f $depbase.Tpo $depbase.Plo
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT png.lo -MD -MP -MF .deps/png.Tpo -c png.c  -fPIC -DPIC -o .libs/png.o
depbase=`echo pngerror.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/sh ./libtool  --tag=CC   --mode=compile /usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngerror.lo -MD -MP -MF $depbase.Tpo -c -o pngerror.lo pngerror.c &&\
mv -f $depbase.Tpo $depbase.Plo
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngerror.lo -MD -MP -MF .deps/pngerror.Tpo -c pngerror.c  -fPIC -DPIC -o .libs/pngerror.o
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngerror.lo -MD -MP -MF .deps/pngerror.Tpo -c pngerror.c  -fPIC -DPIC -o pngerror.o >/dev/null 2>&1
depbase=`echo pngget.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/sh ./libtool  --tag=CC   --mode=compile /usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngget.lo -MD -MP -MF $depbase.Tpo -c -o pngget.lo pngget.c &&\
mv -f $depbase.Tpo $depbase.Plo
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngget.lo -MD -MP -MF .deps/pngget.Tpo -c pngget.c  -fPIC -DPIC -o .libs/pngget.o
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT png.lo -MD -MP -MF .deps/png.Tpo -c png.c  -fPIC -DPIC -o png.o >/dev/null 2>&1
depbase=`echo pngmem.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/sh ./libtool  --tag=CC   --mode=compile /usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngmem.lo -MD -MP -MF $depbase.Tpo -c -o pngmem.lo pngmem.c &&\
mv -f $depbase.Tpo $depbase.Plo
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngmem.lo -MD -MP -MF .deps/pngmem.Tpo -c pngmem.c  -fPIC -DPIC -o .libs/pngmem.o
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngmem.lo -MD -MP -MF .deps/pngmem.Tpo -c pngmem.c  -fPIC -DPIC -o pngmem.o >/dev/null 2>&1
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngget.lo -MD -MP -MF .deps/pngget.Tpo -c pngget.c  -fPIC -DPIC -o pngget.o >/dev/null 2>&1
depbase=`echo pngpread.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/sh ./libtool  --tag=CC   --mode=compile /usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngpread.lo -MD -MP -MF $depbase.Tpo -c -o pngpread.lo pngpread.c &&\
mv -f $depbase.Tpo $depbase.Plo
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngpread.lo -MD -MP -MF .deps/pngpread.Tpo -c pngpread.c  -fPIC -DPIC -o .libs/pngpread.o
depbase=`echo pngread.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/sh ./libtool  --tag=CC   --mode=compile /usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngread.lo -MD -MP -MF $depbase.Tpo -c -o pngread.lo pngread.c &&\
mv -f $depbase.Tpo $depbase.Plo
depbase=`echo pngrio.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/sh ./libtool  --tag=CC   --mode=compile /usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngrio.lo -MD -MP -MF $depbase.Tpo -c -o pngrio.lo pngrio.c &&\
mv -f $depbase.Tpo $depbase.Plo
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngread.lo -MD -MP -MF .deps/pngread.Tpo -c pngread.c  -fPIC -DPIC -o .libs/pngread.o
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngpread.lo -MD -MP -MF .deps/pngpread.Tpo -c pngpread.c  -fPIC -DPIC -o pngpread.o >/dev/null 2>&1
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngrio.lo -MD -MP -MF .deps/pngrio.Tpo -c pngrio.c  -fPIC -DPIC -o .libs/pngrio.o
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngrio.lo -MD -MP -MF .deps/pngrio.Tpo -c pngrio.c  -fPIC -DPIC -o pngrio.o >/dev/null 2>&1
depbase=`echo pngrtran.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/sh ./libtool  --tag=CC   --mode=compile /usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngrtran.lo -MD -MP -MF $depbase.Tpo -c -o pngrtran.lo pngrtran.c &&\
mv -f $depbase.Tpo $depbase.Plo
depbase=`echo pngrutil.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/sh ./libtool  --tag=CC   --mode=compile /usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngrutil.lo -MD -MP -MF $depbase.Tpo -c -o pngrutil.lo pngrutil.c &&\
mv -f $depbase.Tpo $depbase.Plo
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngrtran.lo -MD -MP -MF .deps/pngrtran.Tpo -c pngrtran.c  -fPIC -DPIC -o .libs/pngrtran.o
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngrutil.lo -MD -MP -MF .deps/pngrutil.Tpo -c pngrutil.c  -fPIC -DPIC -o .libs/pngrutil.o
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngread.lo -MD -MP -MF .deps/pngread.Tpo -c pngread.c  -fPIC -DPIC -o pngread.o >/dev/null 2>&1
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngrutil.lo -MD -MP -MF .deps/pngrutil.Tpo -c pngrutil.c  -fPIC -DPIC -o pngrutil.o >/dev/null 2>&1
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngrtran.lo -MD -MP -MF .deps/pngrtran.Tpo -c pngrtran.c  -fPIC -DPIC -o pngrtran.o >/dev/null 2>&1
depbase=`echo pngset.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/sh ./libtool  --tag=CC   --mode=compile /usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngset.lo -MD -MP -MF $depbase.Tpo -c -o pngset.lo pngset.c &&\
mv -f $depbase.Tpo $depbase.Plo
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngset.lo -MD -MP -MF .deps/pngset.Tpo -c pngset.c  -fPIC -DPIC -o .libs/pngset.o
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngset.lo -MD -MP -MF .deps/pngset.Tpo -c pngset.c  -fPIC -DPIC -o pngset.o >/dev/null 2>&1
depbase=`echo pngtrans.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/sh ./libtool  --tag=CC   --mode=compile /usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngtrans.lo -MD -MP -MF $depbase.Tpo -c -o pngtrans.lo pngtrans.c &&\
mv -f $depbase.Tpo $depbase.Plo
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngtrans.lo -MD -MP -MF .deps/pngtrans.Tpo -c pngtrans.c  -fPIC -DPIC -o .libs/pngtrans.o
depbase=`echo pngwio.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/sh ./libtool  --tag=CC   --mode=compile /usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngwio.lo -MD -MP -MF $depbase.Tpo -c -o pngwio.lo pngwio.c &&\
mv -f $depbase.Tpo $depbase.Plo
depbase=`echo pngwrite.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/sh ./libtool  --tag=CC   --mode=compile /usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngwrite.lo -MD -MP -MF $depbase.Tpo -c -o pngwrite.lo pngwrite.c &&\
mv -f $depbase.Tpo $depbase.Plo
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngwio.lo -MD -MP -MF .deps/pngwio.Tpo -c pngwio.c  -fPIC -DPIC -o .libs/pngwio.o
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngwrite.lo -MD -MP -MF .deps/pngwrite.Tpo -c pngwrite.c  -fPIC -DPIC -o .libs/pngwrite.o
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngtrans.lo -MD -MP -MF .deps/pngtrans.Tpo -c pngtrans.c  -fPIC -DPIC -o pngtrans.o >/dev/null 2>&1
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngwio.lo -MD -MP -MF .deps/pngwio.Tpo -c pngwio.c  -fPIC -DPIC -o pngwio.o >/dev/null 2>&1
depbase=`echo pngwtran.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/sh ./libtool  --tag=CC   --mode=compile /usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngwtran.lo -MD -MP -MF $depbase.Tpo -c -o pngwtran.lo pngwtran.c &&\
mv -f $depbase.Tpo $depbase.Plo
depbase=`echo pngwutil.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/sh ./libtool  --tag=CC   --mode=compile /usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngwutil.lo -MD -MP -MF $depbase.Tpo -c -o pngwutil.lo pngwutil.c &&\
mv -f $depbase.Tpo $depbase.Plo
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngwtran.lo -MD -MP -MF .deps/pngwtran.Tpo -c pngwtran.c  -fPIC -DPIC -o .libs/pngwtran.o
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngwutil.lo -MD -MP -MF .deps/pngwutil.Tpo -c pngwutil.c  -fPIC -DPIC -o .libs/pngwutil.o
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngwrite.lo -MD -MP -MF .deps/pngwrite.Tpo -c pngwrite.c  -fPIC -DPIC -o pngwrite.o >/dev/null 2>&1
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngwtran.lo -MD -MP -MF .deps/pngwtran.Tpo -c pngwtran.c  -fPIC -DPIC -o pngwtran.o >/dev/null 2>&1
rm -f libpng.vers
cp scripts/vers.out libpng.vers
depbase=`echo contrib/tools/png-fix-itxt.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\
/usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT contrib/tools/png-fix-itxt.o -MD -MP -MF $depbase.Tpo -c -o contrib/tools/png-fix-itxt.o contrib/tools/png-fix-itxt.c &&\
mv -f $depbase.Tpo $depbase.Po
libtool: compile:  /usr/local/bin/egcc -DHAVE_CONFIG_H -I. -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT pngwutil.lo -MD -MP -MF .deps/pngwutil.Tpo -c pngwutil.c  -fPIC -DPIC -o pngwutil.o >/dev/null 2>&1
depbase=`echo contrib/libtests/pngunknown.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\
/usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT contrib/libtests/pngunknown.o -MD -MP -MF $depbase.Tpo -c -o contrib/libtests/pngunknown.o contrib/libtests/pngunknown.c &&\
mv -f $depbase.Tpo $depbase.Po
depbase=`echo contrib/libtests/pngstest.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\
/usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT contrib/libtests/pngstest.o -MD -MP -MF $depbase.Tpo -c -o contrib/libtests/pngstest.o contrib/libtests/pngstest.c &&\
mv -f $depbase.Tpo $depbase.Po
depbase=`echo contrib/libtests/pngvalid.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\
/usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT contrib/libtests/pngvalid.o -MD -MP -MF $depbase.Tpo -c -o contrib/libtests/pngvalid.o contrib/libtests/pngvalid.c &&\
mv -f $depbase.Tpo $depbase.Po
depbase=`echo contrib/libtests/pngimage.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\
/usr/local/bin/egcc -DHAVE_CONFIG_H -I.   -Og -g -fstack-protector-all -fpic           -I/home/myuser/build/include -L/home/myuser/build/lib -lz   -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -MT contrib/libtests/pngimage.o -MD -MP -MF $depbase.Tpo -c -o contrib/libtests/pngimage.o contrib/libtests/pngimage.c &&\
mv -f $depbase.Tpo $depbase.Po
/bin/sh ./libtool  --tag=CC   --mode=link /usr/local/bin/egcc  -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz -no-undefined -export-dynamic -version-number 16:37:0  -Wl,--version-script=libpng.vers  -L/home/myuser/build/lib -lz  -o libpng.la -rpath /home/myuser/build/lib png.lo pngerror.lo pngget.lo pngmem.lo pngpread.lo pngread.lo pngrio.lo pngrtran.lo pngrutil.lo pngset.lo pngtrans.lo pngwio.lo pngwrite.lo pngwtran.lo pngwutil.lo       -lm -lz -lm -L/home/myuser/build/lib -I/home/myuser/build/include -lz
/bin/sh ./libtool  --tag=CC   --mode=link /usr/local/bin/egcc  -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz  -L/home/myuser/build/lib -lz  -o png-fix-itxt contrib/tools/png-fix-itxt.o  -lm -lz -lm -L/home/myuser/build/lib -I/home/myuser/build/include -lz
libtool: link: /usr/local/bin/egcc -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -o png-fix-itxt contrib/tools/png-fix-itxt.o -I/home/myuser/build/include  -L/home/myuser/build/lib -lm -lz
libtool: link: /usr/local/bin/egcc -shared  -fPIC -DPIC -o .libs/libpng.so.16.37  .libs/png.o .libs/pngerror.o .libs/pngget.o .libs/pngmem.o .libs/pngpread.o .libs/pngread.o .libs/pngrio.o .libs/pngrtran.o .libs/pngrutil.o .libs/pngset.o .libs/pngtrans.o .libs/pngwio.o .libs/pngwrite.o .libs/pngwtran.o .libs/pngwutil.o   -L/home/myuser/build/lib -lm -lz  -Og -g -fstack-protector-all -Wl,--version-script=libpng.vers
libtool: link: ar cru .libs/libpng.a  png.o pngerror.o pngget.o pngmem.o pngpread.o pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
libtool: link: ranlib .libs/libpng.a
libtool: link: ( cd ".libs" && rm -f "libpng.la" && ln -s "../libpng.la" "libpng.la" )
cp libpng.la libpng16.la
/bin/sh ./libtool  --tag=CC   --mode=link /usr/local/bin/egcc  -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz  -L/home/myuser/build/lib -lz  -o pngfix contrib/tools/pngfix.o libpng16.la -lm -lz -lm -L/home/myuser/build/lib -I/home/myuser/build/include -lz
/bin/sh ./libtool  --tag=CC   --mode=link /usr/local/bin/egcc  -Og -g -fstack-protector-all -fpic         -I/home/myuser/build/include -L/home/myuser/build/lib -lz  -L/home/myuser/build/lib -lz  -o pngtest pngtest.o libpng16.la -lm -lz -lm -L/home/myuser/build/lib -I/home/myuser/build/include -lz
libtool: link: /usr/local/bin/egcc -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -o .libs/pngtest pngtest.o -I/home/myuser/build/include  -L/home/myuser/build/lib -L./.libs -lpng16 -lm -lz -Wl,-rpath,/home/myuser/build/lib
libtool: link: /usr/local/bin/egcc -Og -g -fstack-protector-all -fpic -I/home/myuser/build/include -o .libs/pngfix contrib/tools/pngfix.o -I/home/myuser/build/include  -L/home/myuser/build/lib -L./.libs -lpng16 -lm -lz -Wl,-rpath,/home/myuser/build/lib
ld: error: undefined symbol: inflateReset2
>>> referenced by pngfix.c:2184 (contrib/tools/pngfix.c:2184)
>>>               contrib/tools/pngfix.o:(zlib_reset)
collect2: error: ld returned 1 exit status
gmake[1]: *** [Makefile:1038: pngfix] Error 1
gmake[1]: *** Waiting for unfinished jobs....
gmake[1]: Leaving directory '/home/myuser/src/libpng'
gmake: *** [Makefile:820: all] Error 2

[Stuart Henderson]

On 2021-02-23, Bob <[hidden email]> wrote:

> Hi,
>
> I am trying to make a custom build of libpng in my home directory,
> using a libz build that I made in my home directory also.
>
> Both are latest version, libpng 1.6.37 same as OpenBSD's port
> https://cvsweb.openbsd.org/ports/graphics/png/Makefile?rev=1.125&content-type=text/x-cvsweb-markup
> and libz the latest one they published. For zlib it's 1.2.11
> from http://zlib.net/ from 2017, OpenBSD does not have a port but
> base bundles a 2009 version. Since 2009, significantly an export
> "inflateReset2" has been added.

As you have seen it is difficult to have library functions in one
version in base and in another version built elsewhere (whether that's
in $HOME or in ports). Ports only does this for libraries where there's
really no other choice and where that has been done they're used *very*
rarely (the port can then not depend on any libraries which pull in the
library from base). Currently that is libbind (used only by asdig and
zeek) and openssl (used as a static library by sslscan, and dynamic
for nrpe and nsca-ng).

> I'll start with the detail problem, and discuss the reproduction at the
> bottom:
>
>
> This has brought me to the bizarre issue that the libpng build plainly
> refuses to link to my custom libz file /home/myuser/lib/libz.so.1 .
> Instead, it insists with linking to the OS' global
> /usr/lib/libz.so.5.0 .

This is as expected really, it looks for the higher library version
number.

> I have reduced the issue to the libpng build step where it produces
> libpng.so:
>
> /usr/local/bin/egcc -shared  -fPIC -DPIC -o .libs/libpng.so.16.37
> .libs/png.o .libs/pngerror.o .libs/pngget.o .libs/pngmem.o
> .libs/pngpread.o .libs/pngread.o .libs/pngrio.o .libs/pngrtran.o
> .libs/pngrutil.o .libs/pngset.o .libs/pngtrans.o .libs/pngwio.o
> .libs/pngwrite.o .libs/pngwtran.o .libs/pngwutil.o -L/home/myuser/lib
> -lm -lz -Og -g -fstack-protector-all
> [with or without: -Wl,--version-script=libpng.vers]
> [with or without: -Wl,-t]

You might get somewhere further with something like "-nostdlib
-L/home/myuser/lib -L/usr/lib". You might need either rpath or change
to using static libs.

(not relevant to libpng which is in C, but if you try to build C++ software
with GCC rather than Clang you will often run into problems with incompatible
standard libraries too).

> What appears is that GCC ignores the "-L" search path given to it.

-L adds, it doesn't overwrite.

Hopefully you're just doing this to use pngfix; if you try and replace
the installed libpng with one built like this you're likely to end up
with all sorts of problems.

[Marc Espie-2]

On Wed, Feb 24, 2021 at 02:17:14PM -0000, Stuart Henderson wrote:

> On 2021-02-23, Bob <[hidden email]> wrote:
> > Hi,
> >
> > I am trying to make a custom build of libpng in my home directory,
> > using a libz build that I made in my home directory also.
> >
> > Both are latest version, libpng 1.6.37 same as OpenBSD's port
> > https://cvsweb.openbsd.org/ports/graphics/png/Makefile?rev=1.125&content-type=text/x-cvsweb-markup
> > and libz the latest one they published. For zlib it's 1.2.11
> > from http://zlib.net/ from 2017, OpenBSD does not have a port but
> > base bundles a 2009 version. Since 2009, significantly an export
> > "inflateReset2" has been added.
>
> As you have seen it is difficult to have library functions in one
> version in base and in another version built elsewhere (whether that's
> in $HOME or in ports). Ports only does this for libraries where there's
> really no other choice and where that has been done they're used *very*
> rarely (the port can then not depend on any libraries which pull in the
> library from base). Currently that is libbind (used only by asdig and
> zeek) and openssl (used as a static library by sslscan, and dynamic
> for nrpe and nsca-ng).
>
> > I'll start with the detail problem, and discuss the reproduction at the
> > bottom:
> >
> >
> > This has brought me to the bizarre issue that the libpng build plainly
> > refuses to link to my custom libz file /home/myuser/lib/libz.so.1 .
> > Instead, it insists with linking to the OS' global
> > /usr/lib/libz.so.5.0 .
>
> This is as expected really, it looks for the higher library version
> number.

Not really, it's more that you have to make sure to put your own directory
before the system directory, which requires a bit more magic than just -L.

(remember that linking will stop at the first directory with a satisfying
library, and link with the highest version number found in there, which
is fortunate for stuff like libtool!)