[build@build /usr/home/build]$ cat hello.c
int main(int argc, char **argv) {
	return 0;
}
[build@build /usr/home/build]$ clang -c hello.c -march=native
error: unknown target CPU 'athlon-xp'
note: valid target CPU values are: nocona, core2, penryn, bonnell, atom, silvermont, slm, goldmont,
      goldmont-plus, tremont, nehalem, corei7, westmere, sandybridge, corei7-avx, ivybridge, core-avx-i,
      haswell, core-avx2, broadwell, skylake, skylake-avx512, skx, cascadelake, cannonlake,
      icelake-client, icelake-server, knl, knm, k8, athlon64, athlon-fx, opteron, k8-sse3,
      athlon64-sse3, opteron-sse3, amdfam10, barcelona, btver1, btver2, bdver1, bdver2, bdver3, bdver4,
      znver1, x86-64

This is happening because the environment has the CPU name incorrect. It is reporting athlon-xp which is a 32-bit CPU, however the system is 64-bit.

This is causing many tests from Zig's test suite to fail, because it passes -march=native for the native target when importing .h files and compiling C code.