clang/darwin: Don't use response files with ld64

This morally reverts D82777 -- turns out that ld64 crashes with many
response files, so we must stop passing them to it until the crash is
fixed.

Differential Revision: https://reviews.llvm.org/D92357

clang/lib/Driver/ToolChains/Darwin.cpp

@@ -698,7 +698,10 @@ void darwin::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   }
 
   ResponseFileSupport ResponseSupport;
-  if (Version[0] >= 607 || LinkerIsLLDDarwinNew) {
+  if (LinkerIsLLDDarwinNew) {
+    // Xcode12's ld64 added support for @response files, but it's crashy:
+    // https://openradar.appspot.com/radar?id=4933317065441280
+    // FIXME: Pass this for ld64 once it no longer crashes.
     ResponseSupport = ResponseFileSupport::AtFileUTF8();
   } else {
     // For older versions of the linker, use the legacy filelist method instead.