Created attachment 1753927 [details]
build.log

file build.log too big, will only attach last 32768 bytes

Created attachment 1753928 [details]
root.log

file root.log too big, will only attach last 32768 bytes

Created attachment 1753929 [details]
state.log

Builds with gcc-11.0.0-0.16.fc34  but fails with gcc-11.0.0-0.17.fc34.

It looks like compiler-rt's feature checks are getting confused and it thinks the compiler supports these flags: /wd4146 /wd4291 /wd4391 /wd4722 /wd4800  But gcc complains about this.

Here is a small reproducer that demonstrates the change in behavior:

gcc-10.2.1-9.fc33:

echo 'int main() { return 0; }' | gcc /wd48000 -x c -c -
gcc: error: /wd48000: No such file or directory

gcc-11.0.0-0.18.fc34:

echo 'int main() { return 0; }' | g++ /wd48000 -x c -c -
g++: warning: /wd48000: linker input file unused because linking not done


compiler-rt uses the standard cmake function: check_cxx_compiler_flag[1] to check for supported compiler flags, so it's likely that other packages that use cmake and check for this kind of flag could also hit the same problem.

[1] https://cmake.org/cmake/help/latest/module/CheckCXXCompilerFlag.html

sorry about that,  this patch is now on trunk:

6606b852bfa 2021-02-04 | driver: error for nonexistent linker inputs [PR 98943]

This bug appears to have been reported against 'rawhide' during the Fedora 34 development cycle.
Changing version to 34.