Let amd64 be used in target triple instead of x86_64 on FreeBSD.

Patch by Dimitry Andric!

llvm-svn: 131990
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index b959459..ccc7643 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -778,7 +778,8 @@
       else if (getToolChain().getArchName() == "i386")
         CPUName = "i486";
     } else if (getToolChain().getOS().startswith("freebsd"))  {
-      if (getToolChain().getArchName() == "x86_64")
+      if (getToolChain().getArchName() == "x86_64" ||
+          getToolChain().getArchName() == "amd64")
         CPUName = "x86-64";
       else if (getToolChain().getArchName() == "i386")
         CPUName = "i486";