freetype: patch pkg-config in -config better

When we have build == host != target, we don't want to patch in a
prefixed pkg-config used for cross compiling. Using `pkgsHostHost`
expressses the intent.

Then again, per https://github.com/NixOS/nixpkgs/issues/51176 leaving
`buildPackages.pkg-config` is arguably also correct, if we do further
cross compilation and want to run `freetype-config`. Really, there is no
good solution.

pkgs/development/libraries/freetype/default.nix

@@ -1,5 +1,5 @@
 { lib, stdenv, fetchurl
-, buildPackages
+, buildPackages, pkgsHostHost
 , pkg-config, which, makeWrapper
 , zlib, bzip2, libpng, gnumake, glib
 
@@ -64,7 +64,7 @@ in stdenv.mkDerivation rec {
 
   postInstall = glib.flattenInclude + ''
     substituteInPlace $dev/bin/freetype-config \
-      --replace ${buildPackages.pkg-config} ${pkg-config}
+      --replace ${buildPackages.pkg-config} ${pkgsHostHost.pkg-config}
 
     wrapProgram "$dev/bin/freetype-config" \
       --set PKG_CONFIG_PATH "$PKG_CONFIG_PATH:$dev/lib/pkgconfig"