Update x86 CPU detection configure check.

Commit 6577534a switched from using __get_cpuid() to
 __get_cpuid_count(), but the corresponding configure check was not
Since __get_cpuid_count() was introduced much later, make sure we
 check for the function we actually use.

Thanks to Mark Harris for the report.
10 jobs for intrinsic_fixes4 in 4 minutes and 53 seconds (queued for 103 minutes and 9 seconds)