Driver: Add a toolchain hook for whether the system has native LLVM support.

llvm-svn: 114137
diff --git a/clang/lib/Driver/ToolChains.cpp b/clang/lib/Driver/ToolChains.cpp
index 471c47d..f5b4559 100644
--- a/clang/lib/Driver/ToolChains.cpp
+++ b/clang/lib/Driver/ToolChains.cpp
@@ -59,6 +59,10 @@
   return Ty;
 }
 
+bool Darwin::HasNativeLLVMSupport() const {
+  return true;
+}
+
 // FIXME: Can we tablegen this?
 static const char *GetArmArchForMArch(llvm::StringRef Value) {
   if (Value == "armv6k")