Revert "qt5.qtbase: fix build on darwin"

The ld64 issue has been fixed.

This reverts commit 17cafcb365.

pkgs/development/libraries/qt-5/modules/qtbase.nix

@@ -20,8 +20,6 @@
   which,
   # darwin support
   xcbuild,
-  # TODO: Clean up on `staging`
-  llvmPackages,
 
   dbus,
   fontconfig,
@@ -194,8 +192,6 @@ stdenv.mkDerivation (
       ]
       ++ lib.optionals stdenv.hostPlatform.isDarwin [
         xcbuild
-        # TODO: Clean up on `staging`
-        llvmPackages.lld
       ];
 
     }
@@ -377,12 +373,6 @@ stdenv.mkDerivation (
         # if dependency paths contain the string "pq", which can occur in the hash.
         # To prevent these failures, we need to override PostgreSQL detection.
         PSQL_LIBS = "-L${libpq}/lib -lpq";
-      }
-      // lib.optionalAttrs stdenv.hostPlatform.isDarwin {
-        # Fix for ld64 hardening issue
-        #
-        # TODO: Clean up on `staging`
-        NIX_CFLAGS_LINK = "-fuse-ld=lld";
       };
 
       prefixKey = "-prefix ";