Add -ccc-install-dir option for faking installation path.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@81017 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/Driver.cpp b/lib/Driver/Driver.cpp
index 087dc57..e3d812d 100644
--- a/lib/Driver/Driver.cpp
+++ b/lib/Driver/Driver.cpp
@@ -191,6 +191,10 @@
       assert(Start+1 < End && "FIXME: -ccc- argument handling.");
       HostTriple = *++Start;
 
+    } else if (!strcmp(Opt, "install-dir")) {
+      assert(Start+1 < End && "FIXME: -ccc- argument handling.");
+      Dir = *++Start;
+
     } else {
       // FIXME: Error handling.
       llvm::errs() << "invalid option: " << *Start << "\n";
@@ -366,7 +370,9 @@
 
     OptionHelp.push_back(std::make_pair("\nDEBUG/DEVELOPMENT OPTIONS:",""));
     OptionHelp.push_back(std::make_pair("-ccc-host-triple",
-                                        "Simulate running on the given target"));
+                                       "Simulate running on the given target"));
+    OptionHelp.push_back(std::make_pair("-ccc-install-dir",
+                               "Simulate installation in the given directory"));
     OptionHelp.push_back(std::make_pair("-ccc-print-options",
                                         "Dump parsed command line arguments"));
     OptionHelp.push_back(std::make_pair("-ccc-print-phases",