Don't perform CET run-time check for host when cross compiling. Instead,
enable CET in cross compiler if possible so that it will run on both CET
and non-CET hosts.
config/
PR bootstrap/94998
* cet.m4 (GCC_CET_HOST_FLAGS): Enable CET in cross compiler if
possible.
libiberty/
PR bootstrap/94998
* configure: Regenerated.
lto-plugin/
PR bootstrap/94998
* configure: Regenerated.