When glibc is built with ISA level 3 or higher by default, the resulting
glibc binaries won't run on SSE or FMA4 processors. Exclude SSE, AVX and
FMA4 variants in libm multiarch when ISA level 3 or higher is enabled by
default.
When glibc is built with ISA level 2 enabled by default, only keep SSE4.1
variant.
Fixes BZ 31335.
NB: elf/tst-valgrind-smoke test fails with ISA level 4, because valgrind
doesn't support AVX512 instructions:
https://bugs.kde.org/show_bug.cgi?id=383010
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
