Revert "Refactor mkFlag out of old packages"

This reverts commit 3117e0c897.

Conflicts:
	pkgs/development/libraries/wayland/default.nix
	pkgs/servers/samba/4.x.nix

pkgs/development/libraries/libass/default.nix

@@ -11,6 +11,10 @@ assert encaSupport -> enca != null;
 assert fontconfigSupport -> fontconfig != null;
 assert harfbuzzSupport -> harfbuzz != null;
 
+let
+  mkFlag = optSet: flag: if optSet then "--enable-${flag}" else "--disable-${flag}";
+in
+
 with stdenv.lib;
 stdenv.mkDerivation rec {
   name = "libass-${version}";
@@ -22,11 +26,11 @@ stdenv.mkDerivation rec {
   };
 
   configureFlags = [
-    (mkEnable encaSupport       "enca"        null)
-    (mkEnable fontconfigSupport "fontconfig"  null)
-    (mkEnable harfbuzzSupport   "harfbuzz"    null)
-    (mkEnable rasterizerSupport "rasterizer"  null)
-    (mkEnable largeTilesSupport "large-tiles" null)
+    (mkFlag encaSupport "enca")
+    (mkFlag fontconfigSupport "fontconfig")
+    (mkFlag harfbuzzSupport "harfbuzz")
+    (mkFlag rasterizerSupport "rasterizer")
+    (mkFlag largeTilesSupport "large-tiles")
   ];
 
   nativeBuildInputs = [ pkgconfig yasm ];