[Bug target/78417] target_clones default for powerpc64

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78417

--- Comment #5 from Segher Boessenkool <segher at gcc dot gnu.org> ---
It now says

78417-1.c:10:15: error: target_clones attribute needs GLIBC (2.23 and newer)
that exports hardware capability bits
 static double foo_int(const double *restrict a, const double *restrict b, int
n)
               ^~~~~~~
78417-1.c:10:15: error: default 'target_clones' attribute was not set

on systems with older glibc, and seems to work fine on systems with new
enough glibc.