fontconfig: Fix for HFS+ 1s date resolution issue

HFS+ (still common on macOS machines) only has a
date resolution of 1 second.  This change makes sure that
`fcobjshash.h` gets a newer timestamp than `fcobjshash.gperf`.

pkgs/development/libraries/fontconfig/default.nix

@@ -39,7 +39,8 @@ stdenv.mkDerivation rec {
   # additionally required for the glibc-2.25 patch; avoid requiring gperf
   postPatch = ''
     sed s/CHAR_WIDTH/CHARWIDTH/g -i src/fcobjshash.{h,gperf}
-    touch src/*
+    sleep 2
+    touch src/fcobjshash.h
   '';
 
   outputs = [ "bin" "dev" "lib" "out" ]; # $out contains all the config