Fix the fails of make check when SOURCE_DATE_EPOCH is set

Fixes fontconfig/fontconfig#172
3 jobs for issue/172 in 12 minutes and 7 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Build
passed mingw-build #461515

00:12:06

passed shared-build #461513

00:05:50

passed static-build #461514

00:04:26