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/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 796fd64..96971e9 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -2482,6 +2482,7 @@
       TC = new toolchains::Minix(*this, Target, Args);
       break;
     case llvm::Triple::Linux:
+    case llvm::Triple::ELFIAMCU:
       if (Target.getArch() == llvm::Triple::hexagon)
         TC = new toolchains::HexagonToolChain(*this, Target, Args);
       else if ((Target.getVendor() == llvm::Triple::MipsTechnologies) &&