Compilation for Intel MCU (Part 2/3)

This is the second patch required to support compilation for Intel MCU target (e.g. Intel(R) Quark(TM) micro controller D 2000).
When IAMCU triple is used:
 * Recognize and use IAMCU GCC toolchain
 * Set up include paths
 * Forbid C++

Differential Revision: http://reviews.llvm.org/D19274

llvm-svn: 272883
diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index 5855bef..cba8924 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -696,3 +696,6 @@
 
 void ToolChain::AddCudaIncludeArgs(const ArgList &DriverArgs,
                                    ArgStringList &CC1Args) const {}
+
+void ToolChain::AddIAMCUIncludeArgs(const ArgList &DriverArgs,
+                                    ArgStringList &CC1Args) const {}