Hey! > I’d rather go for #2. To do that, we could modify the ‘set-paths’ phase > to manually remove glibc from C_INCLUDE_PATH (fragile), or we could > modify GCC (perhaps removing the ‘remove_duplicates’ call for SYSTEM). > > Either way, this wouldn’t work well with ‘guix environment’, where glibc > ends up in /gnu/store/…-profile, so it does not appear as duplicate to > GCC. [...] > Looking at ‘cppdefault.c’ in GCC, I don’t see where glibc-2.31/include > comes from; it seems that ‘INCLUDE_DEFAULTS’ is undefined on glibc > systems. It's indeed undefined and glibc comes from NATIVE_SYSTEM_HEADER_DIR at the end of the file you mentioned. It is a consequence of passing --with-native-system-header-dir=glibc in (gnu packages gcc). About the environment issue, we have the same problem on master. You can run the following command: > > Thoughts? > > Incidentally, do we have problems building anything other than QEMU? > > Thanks, > Ludo’.