https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80677
Sam James <sjames at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
See Also| |https://bugs.gentoo.org/sho
| |w_bug.cgi?id=854834
--- Comment #8 from Sam James <sjames at gcc dot gnu.org> ---
The case that I hit it in was with Gentoo's crossdev but we don't use the
Debian multilib layout at all, nor do we patch anything like that in.
There's some analysis at https://bugs.gentoo.org/854834#c0 (which I ended up
rediscovering, only found that bug report this weekend):
"""
My understanding of what GCC (cross-arm-none-eabi/gcc-12.1.1_p20220625) does
when it is building itself is that it attempts to locate an existing limits.h
header, and if it does, it adds some forwarding wrappers around its own
implementation to also include the found limits.h. However, in my case GCC was
not finding newlib's limits.h header.
Debugging the GCC build process led me to the gcc/Makefile in the build
directory. In here, a check is defined by the LIMITS_H_TEST variable. Hacking
together something so I can see what that expands to at the time of the check,
I was able to identify it as the following:
[ -f /usr/arm-none-eabi/usr/include/limits.h ]
Of note, this header _does not_ exist. Newlib installed its header to
/usr/arm-none-eabi/include/limits.h (note the missing usr between the triplet
and the include). In other words, GCC is looking for the header (per the
Makefile) in the cross-compiler-prefix + /usr/include.
I haven't tried it yet, but it may be possible to fix this by telling GCC to
look in cross-compiler-prefix + /include possibly with the use of
--with-native-system-header-dir=/include . Alternatively, if it's possible to
have newlib install to /usr/arm-none-eabi/usr/, for example, GCC should pick up
the headers.
By hacking the Makefile to use `NATIVE_SYSTEM_HEADER_DIR = /include` instead of
`NATIVE_SYSTEM_HEADER_DIR = /usr/include`, I was able to get GCC to find the
newlib limits.h header and set up its own limits.h header properly.
"""
