[driver] Don't try to set the deployment target when there is no bound
architecture; this was happening for tools such as lipo and dsymutil.
Also, if no -arch option has been specified, set the architecture based
on the TC default.
rdar://11329656

llvm-svn: 155730
diff --git a/clang/lib/Driver/ToolChains.cpp b/clang/lib/Driver/ToolChains.cpp
index b56add3..c883e44 100644
--- a/clang/lib/Driver/ToolChains.cpp
+++ b/clang/lib/Driver/ToolChains.cpp
@@ -956,7 +956,8 @@
   // Add an explicit version min argument for the deployment target. We do this
   // after argument translation because -Xarch_ arguments may add a version min
   // argument.
-  AddDeploymentTarget(*DAL);
+  if (BoundArch)
+    AddDeploymentTarget(*DAL);
 
   // Validate the C++ standard library choice.
   CXXStdlibType Type = GetCXXStdlibType(*DAL);