Build failure on musl libc with gcc-15

[hhoffstaette]

Reported in Gentoo as bug 944114

The included getopt.h only declares a proper getopt prototype for glibc and otherwise ("not __GNU_LIBRARY__") declares it as extern int getopt(), which fails to compile with gcc-15.
Simply using the same protoype as for glibc makes it build & work fine - see the patch attached to the aforementioned bug.
Edit: apparently this was fixed long ago in gnulib: coreutils/gnulib@1c64ecc

[twaugh]

Can you please try again now I've merged #75 ?

[hhoffstaette]

Tried to bootstrap in my musl chroot and now get a different error..about error() 🤪
boostrap.log

This is because error() is also GNU specific. On Gentoo we have a separate error-standalone package, but installing that & rebootstrapping/configuring unfortunately did not help either, even though configure finds it and says: checking for error.h... (cached) yes.

It looks like gnulib generates its own error.h unconditionally, and whatever it generates is broken..or something.
Edit: Actually! It configures & builds fine when I forcefully uninstall error-standalone and let gnulib do its thing. So gnulib needs to recognize when error.h is available and not try to use its own implementation. I missed the fact that I had error-standalone already installed during my original attempt.

[hhoffstaette]

When I remove all error.* stuff from lib, reconfigure and LDFLAGS="-lerror" (to add error-stanadalone) it builds and works fine as well.

[hhoffstaette]

So AFAICT this problem with the presence of error-standalone is a bit of a self-inflicted problem on Gentoo, but I found a way to work around it after bootstrap/configure, which should also work with a packaged tarball (truncate -s 0 lib/error.h lib/error.c after configure and LDFLAGS="-lerror" for building). We might raise this with the gnulib people, but for now I consider this "fixed upstream". Thank you! 🙌

[hhoffstaette]

Closing since the original problem is fixed. Thanks again.