Inject gnueabihf environment into the effective clang triple for NaCl

lib/Driver/ToolChains.h

Index: lib/Driver/ToolChains.h
diff --git a/lib/Driver/ToolChains.h b/lib/Driver/ToolChains.h
index f6ab550c87f6b4b7e87be973f4647629ea36c773..c67b269bf554956ca3a3162e59e36f7ed827f422 100644
--- a/lib/Driver/ToolChains.h
+++ b/lib/Driver/ToolChains.h
@@ -741,6 +741,9 @@ public:
   // because the AssembleARM tool needs a const char * that it can pass around
   // and the toolchain outlives all the jobs.
   const char *GetNaClArmMacrosPath() const { return NaClArmMacrosPath.c_str(); }
+
+  std::string ComputeEffectiveClangTriple(const llvm::opt::ArgList &Args,
+                                          types::ID InputType) const override;
   std::string Linker;
 
 protected: