Sink the handling of -fobjc-arc-cxxlib to live with the other -fobjc-arc
implementation in the driver. This cleans up the signature and semantics
of the include flag adding component of the toolchain. Another step to
ready it for holding all the InitHeaderSearch logic.

llvm-svn: 143686
diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index 88c3956..11deed1 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -231,23 +231,8 @@
 }
 
 void ToolChain::AddClangCXXStdlibIncludeArgs(const ArgList &Args,
-                                             ArgStringList &CmdArgs,
-                                             bool ObjCXXAutoRefCount) const {
-  CXXStdlibType Type = GetCXXStdlibType(Args);
-
+                                             ArgStringList &CmdArgs) const {
   // Header search paths are handled by each of the subclasses.
-
-  switch (Type) {
-  case ToolChain::CST_Libcxx:
-    if (ObjCXXAutoRefCount)
-      CmdArgs.push_back("-fobjc-arc-cxxlib=libc++");
-    break;
-
-  case ToolChain::CST_Libstdcxx:
-    if (ObjCXXAutoRefCount)
-      CmdArgs.push_back("-fobjc-arc-cxxlib=libstdc++");
-    break;
-  }
 }
 
 void ToolChain::AddCXXStdlibLibArgs(const ArgList &Args,