Driver: Add test case for darwin::Preprocess and darwin::Compile
tools, and enable them.

llvm-svn: 68019
diff --git a/clang/lib/Driver/ToolChains.cpp b/clang/lib/Driver/ToolChains.cpp
index 1b0bdfa..8bbf2a6 100644
--- a/clang/lib/Driver/ToolChains.cpp
+++ b/clang/lib/Driver/ToolChains.cpp
@@ -111,13 +111,12 @@
     case Action::BindArchClass:
       assert(0 && "Invalid tool kind.");
     case Action::PreprocessJobClass:
-      T = new tools::gcc::Preprocess(*this); break;
-    case Action::PrecompileJobClass:
-      T = new tools::gcc::Precompile(*this); break;
+      T = new tools::darwin::Preprocess(*this); break;
     case Action::AnalyzeJobClass:
       T = new tools::Clang(*this); break;
+    case Action::PrecompileJobClass:
     case Action::CompileJobClass:
-      T = new tools::gcc::Compile(*this); break;
+      T = new tools::darwin::Compile(*this); break;
     case Action::AssembleJobClass:
       T = new tools::darwin::Assemble(*this); break;
     case Action::LinkJobClass: