Enhance `mkstemps` detection on linux with glibc version sniffing.

`mkstemps` was added to glibc in version 2.11 and as such may not be
available on all glibc-based platforms.
Merge pull request #1247 from dark-panda/fix-mkstemps

Enhance `mkstemps` detection on linux with glibc version sniffing.