fontconfig build fixes for Windows, needed for 1.19.1
fontconfig.recipe: Fix post-install on rebuild
The symlink will already exist, and we'll get an error that it
already exists. Backport fixes from fontconfig master that fix it.
fontconfig.recipe: Don't detect FC_GPERF_SIZE_T
Upstream MR: fontconfig/fontconfig!178
Edited by Nirbheek Chauhan