libffi: refactor meta

pkgs/development/libraries/libffi/default.nix

@@ -26,7 +26,7 @@ stdenv.mkDerivation rec {
     ln -s${if (stdenv.isFreeBSD || stdenv.isOpenBSD || stdenv.isDarwin) then "" else "r"}v "$out/lib/"libffi*/include "$out/include"
   '';
 
-  meta = {
+  meta = with stdenv.lib; {
     description = "A foreign function call interface library";
     longDescription = ''
       The libffi library provides a portable, high level programming
@@ -44,8 +44,8 @@ stdenv.mkDerivation rec {
     '';
     homepage = http://sourceware.org/libffi/;
     # See http://github.com/atgreen/libffi/blob/master/LICENSE .
-    license = stdenv.lib.licenses.free;
+    license = licenses.free;
     maintainers = [ ];
-    platforms = stdenv.lib.platforms.all;
+    platforms = platforms.all;
   };
 }