Un-namespace-qualify llvm_unreachable. It's a macro, so the qualification gave
no extra safety anyway.

llvm-svn: 91207
diff --git a/clang/lib/Driver/ToolChains.cpp b/clang/lib/Driver/ToolChains.cpp
index af63952..420573d 100644
--- a/clang/lib/Driver/ToolChains.cpp
+++ b/clang/lib/Driver/ToolChains.cpp
@@ -510,7 +510,7 @@
       DAL->append(DAL->MakeJoinedArg(0, MArch, "armv7a"));
 
     else
-      llvm::llvm_unreachable("invalid Darwin arch");
+      llvm_unreachable("invalid Darwin arch");
   }
 
   return DAL;