FcConfigParseAndLoad*() should returns false on config errors

Fixes fontconfig/fontconfig#168

Reported by Lawrence D'Oliveiro
3 jobs for issue/168 in 5 minutes and 37 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed mingw-build #436194

00:04:42

passed shared-build #436192

00:05:37

passed static-build #436193

00:04:29