Determining if the backtrace exist failed with the following output:
Change Dir: /var/tmp/portage/sys-apps/cpu-x-4.4.0/work/CPU-X-4.4.0_build/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/ninja cmTC_d5511 && [1/2] Building C object CMakeFiles/cmTC_d5511.dir/CheckSymbolExists.c.o
FAILED: CMakeFiles/cmTC_d5511.dir/CheckSymbolExists.c.o 
/usr/bin/x86_64-gentoo-linux-musl-gcc    -O2 -pipe -march=x86-64 -frecord-gcc-switches -fno-diagnostics-color -fmessage-length=0 -Wno-deprecated-declarations -Wno-unused-result -o CMakeFiles/cmTC_d5511.dir/CheckSymbolExists.c.o -c /var/tmp/portage/sys-apps/cpu-x-4.4.0/work/CPU-X-4.4.0_build/CMakeFiles/CMakeTmp/CheckSymbolExists.c
/var/tmp/portage/sys-apps/cpu-x-4.4.0/work/CPU-X-4.4.0_build/CMakeFiles/CMakeTmp/CheckSymbolExists.c:2:10: fatal error: execinfo.h: No such file or directory
    2 | #include <execinfo.h>
      |          ^~~~~~~~~~~~
compilation terminated.
ninja: build stopped: subcommand failed.


File /var/tmp/portage/sys-apps/cpu-x-4.4.0/work/CPU-X-4.4.0_build/CMakeFiles/CMakeTmp/CheckSymbolExists.c:
/* */
#include <execinfo.h>

int main(int argc, char** argv)
{
  (void)argv;
#ifndef backtrace
  return ((int*)(&backtrace))[argc];
#else
  (void)argc;
  return 0;
#endif
}