graphite2: Remove libgcc

It doesn't seem to be needed.

pkgs/development/libraries/silgraphite/graphite2.nix

···
 , freetype
 , cmake
 , static ? stdenv.hostPlatform.isStatic
-, libgcc
 }:
 
 stdenv.mkDerivation rec {
···
   };
 
   nativeBuildInputs = [ pkg-config cmake ];
-  buildInputs = [ freetype ]
-    # On aarch64-darwin libgcc won't even build currently, and it doesn't seem needed.
-    ++ lib.optionals (with stdenv; !cc.isGNU && !(isDarwin && isAarch64)) [ libgcc ];
+  buildInputs = [ freetype ];
 
   patches = lib.optionals stdenv.isDarwin [ ./macosx.patch ];