Add stack alignment to x86_64 target data.
 - <rdar://problem/6948443> WARNING: Linking two modules of different data
   layouts!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@73093 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index b933bfe..8b04920 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -970,7 +970,7 @@
 
     DescriptionString = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-"
                         "i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-"
-                        "a0:0:64-f80:128:128";
+                        "a0:0:64-s0:64:64-f80:128:128";
   }
   virtual const char *getVAListDeclaration() const {
     return "typedef struct __va_list_tag {"