Merge 'mingw-w64' and 'darwin' into cross-win-osx.

Both branches have quite a lot in common, so it's time for a merge and
do the cleanups with respect to both implementations and also generalize
both implementations as much as possible.

This also closes #1876.

Conflicts:
	pkgs/development/interpreters/lua-5/5.2.nix
	pkgs/development/libraries/SDL/default.nix
	pkgs/development/libraries/glew/default.nix
	pkgs/top-level/all-packages.nix

pkgs/development/libraries/glew/default.nix

@@ -1,5 +1,7 @@
 { stdenv, fetchurl, mesa_glu, x11, libXmu, libXi }:
 
+with stdenv.lib;
+
 stdenv.mkDerivation rec {
   name = "glew-1.10.0";
 
@@ -8,23 +10,38 @@ stdenv.mkDerivation rec {
     sha256 = "01zki46dr5khzlyywr3cg615bcal32dazfazkf360s1znqh17i4r";
   };
 
-
-  buildInputs = [ x11 libXmu libXi ];
-  propagatedBuildInputs = [ mesa_glu ]; # GL/glew.h includes GL/glu.h
+  nativeBuildInputs = [ x11 libXmu libXi ];
+  propagatedNativeBuildInputs = [ mesa_glu ]; # GL/glew.h includes GL/glu.h
 
   patchPhase = ''
     sed -i 's|lib64|lib|' config/Makefile.linux
+    ${optionalString (stdenv ? cross) ''
+    sed -i -e 's/\(INSTALL.*\)-s/\1/' Makefile
+    ''}
   '';
 
-buildPhase = "make all";
-  installPhase = ''
-    GLEW_DEST=$out make install.all
+  buildFlags = [ "all" ];
+  installFlags = [ "install.all" ];
+
+  preInstall = ''
+    export GLEW_DEST="$out"
+  '';
+
+  postInstall = ''
     mkdir -pv $out/share/doc/glew
     mkdir -p $out/lib/pkgconfig
     cp glew*.pc $out/lib/pkgconfig
     cp -r README.txt LICENSE.txt doc $out/share/doc/glew
   '';
 
+  crossAttrs.makeFlags = [
+    "CC=${stdenv.cross.config}-gcc"
+    "LD=${stdenv.cross.config}-gcc"
+    "AR=${stdenv.cross.config}-ar"
+    "STRIP="
+  ] ++ optional (stdenv.cross.libc == "msvcrt") "SYSTEM=mingw"
+    ++ optional (stdenv.cross.libc == "libSystem") "SYSTEM=darwin";
+
   meta = {
     description = "An OpenGL extension loading library for C(++)";
     homepage = http://glew.sourceforge.net/;