Build and use libcompiler_rt whenever possible.

Patch by Jean-Daniel Dupas!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@133624 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/ToolChains.h b/lib/Driver/ToolChains.h
index 7325874..9ed0dc2 100644
--- a/lib/Driver/ToolChains.h
+++ b/lib/Driver/ToolChains.h
@@ -175,7 +175,7 @@
   /// runtime library.
   virtual void AddLinkRuntimeLibArgs(const ArgList &Args,
                                      ArgStringList &CmdArgs) const = 0;
-
+  
   /// }
   /// @name ToolChain Implementation
   /// {
@@ -266,7 +266,9 @@
 
   virtual void AddLinkRuntimeLibArgs(const ArgList &Args,
                                      ArgStringList &CmdArgs) const;
-
+  void AddLinkRuntimeLib(const ArgList &Args, ArgStringList &CmdArgs, 
+                         const char *DarwinStaticLib) const;
+  
   virtual void AddCXXStdlibLibArgs(const ArgList &Args,
                                    ArgStringList &CmdArgs) const;