Made more libraries cross compile. fontconfig, libxcb, bzip2, libdrm, zlib...

I was trying to cross compile SDL. Many dependencies work, but I ended seeing
libX11 not ready for cross compilation. Other xorg libraries cross-compile
well. libX11 may need a small patch. The problem is the usual "configure test
cannot be run in cross compilation", so the configure script halts.

I made the pkgconfig expression always return buildDrv, as I think it rarely
will be needed as buildInput. So to avoid rewriting all its mentions to use
it as buildNativeInput, I prefered this small change.


svn path=/nixpkgs/branches/stdenv-updates/; revision=18500

pkgs/development/libraries/fontconfig/default.nix

@@ -13,6 +13,14 @@ stdenv.mkDerivation rec {
 
   configureFlags = "--with-confdir=/etc/fonts --with-cache-dir=/var/cache/fontconfig --disable-docs --with-default-fonts=";
 
+  crossArch = stdenv.cross.arch;
+
+  preConfigure = ''
+    if test -n "$crossConfig"; then
+      configureFlags="$configureFlags --with-arch=$crossArch";
+    fi
+  '';
+
   # Don't try to write to /etc/fonts or /var/cache/fontconfig at install time.
   installFlags = "CONFDIR=$(out)/etc/fonts RUN_FC_CACHE_TEST=false fc_cachedir=$(TMPDIR)/dummy";