swift-corefoundation: some cleanup

I upstreamed some patches so I'm using those now

pkgs/os-specific/darwin/swift-corefoundation/default.nix

···
   src = fetchFromGitHub {
     owner  = "apple";
     repo   = "swift-corelibs-foundation";
-    rev    = "87d1a97d6af07fec568765c47daddff0aaa0d59c";
-    sha256 = "05cmqwzqqxb489g9hq7hhj2yva12pi488iblbpnvyk1y4nx077cw";
+    rev    = "dce4233f583ec15190b240d6116396bf9641cd57";
+    sha256 = "0i2ldvy14x05k2vgl5z0g5l2i5llifdfbij5zwfdwb8jmmq215qr";
   };
 
   buildInputs = [ ninja python libxml2 ];
 
   patchPhase = ''
-    HACK=$PWD/hack
-    mkdir -p $HACK/CoreFoundation
-    cp CoreFoundation/Base.subproj/CFAsmMacros.h $HACK/CoreFoundation
-
     substituteInPlace CoreFoundation/build.py \
-      --replace "','" "'," \
       --replace '-I''${SYSROOT}/usr/include/libxml2' '-I${libxml2.dev}/include/libxml2' \
-      --replace 'cf.ASFLAGS = " ".join([' "cf.ASFLAGS = ' '.join([ '-I$HACK', " \
   '';
 
-  configureFlags = "--sysroot unused";
+  configurePhase = ":";
 
   buildPhase = ''
     cd CoreFoundation
-    ../configure --sysroot foo
+    ../configure --sysroot unused
     ninja
   '';