Revert r148138; it's causing test failures.

llvm-svn: 148141
diff --git a/clang/tools/driver/driver.cpp b/clang/tools/driver/driver.cpp
index e399790..24fd1ba 100644
--- a/clang/tools/driver/driver.cpp
+++ b/clang/tools/driver/driver.cpp
@@ -271,7 +271,7 @@
   // the function tries to identify a target as prefix. E.g.
   // "x86_64-linux-clang" as interpreted as suffix "clang" with
   // target prefix "x86_64-linux". If such a target prefix is found,
-  // is gets added via -target as implicit first argument.
+  // is gets added via -ccc-host-triple as implicit first argument.
   static const struct {
     const char *Suffix;
     bool IsCXX;
@@ -331,7 +331,7 @@
       ++it;
     ArgVector.insert(it, SaveStringInSet(SavedStrings, Prefix));
     ArgVector.insert(it,
-      SaveStringInSet(SavedStrings, std::string("-target")));
+      SaveStringInSet(SavedStrings, std::string("-ccc-host-triple")));
   }
 }