Here is a fix  for libaudiofile that allows building  with
ports-gcc-6.4 on macppc.
I can't do better than quoting the patch commit message:
libaudiofile: fix the second undefined behaviour in the same line of
code, cstatic which isn't actually a cstatic. switch to just defining
it in the accessor. GCC optimized this undefined behaviour away leading
to an undefined reference in the builds.
- 'make test' passes (see )
- i've built audio/normalize without issues, the runtime  is as
expected. Same thing using ports-gcc-4.9.
- it doesn't break the amd64 build and audio/normalize runtime is fine
there as well.