[Driver] Fix a typo in the setting of the arch name when -arch x86_64h is used.
<rdar://problem/15711488>

llvm-svn: 198722
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index afe26db..745497f 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -1879,7 +1879,7 @@
     // Handle the Darwin '-arch' flag.
     if (Arg *A = Args.getLastArg(options::OPT_arch)) {
       if (StringRef(A->getValue()) == "x86_64h")
-        Target.setArchName(DarwinArchName);
+        Target.setArchName(A->getValue());
       else {
         llvm::Triple::ArchType DarwinArch
           = tools::darwin::getArchTypeForDarwinArchName(A->getValue());