Driver: Fix thinko in logic for finding gcc's tool chain directory.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@84805 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index 398e5dd..ae8119d 100644
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -65,7 +65,8 @@
   ToolChainDir += llvm::utostr(GCCVersion[2]);
 
   // Try the next major version if that tool chain dir is invalid.
-  if (!llvm::sys::Path(ToolChainDir).exists()) {
+  std::string Tmp = "/usr/lib/gcc/" + ToolChainDir;
+  if (!llvm::sys::Path(Tmp).exists()) {
     std::string Next = "i686-apple-darwin";
     Next += llvm::utostr(DarwinVersion[0] + 1);
     Next += "/";
@@ -78,7 +79,8 @@
     // Use that if it exists, otherwise hope the user isn't linking.
     //
     // FIXME: Drop dependency on gcc's tool chain.
-    if (llvm::sys::Path(Next).exists())
+    Tmp = "/usr/lib/gcc/" + Next;
+    if (llvm::sys::Path(Tmp).exists())
       ToolChainDir = Next;
   }