Add an option `-enable-old-style-attr-syntax' to print out function attributes in the "old" style.

It's sometimes beneficial to emit a testcase with the old style attribute
syntax. Allow someone to do this.
<rdar://problem/13563209>

llvm-svn: 179735
diff --git a/llvm/lib/IR/AttributeImpl.h b/llvm/lib/IR/AttributeImpl.h
index ad2670d..7d34c72 100644
--- a/llvm/lib/IR/AttributeImpl.h
+++ b/llvm/lib/IR/AttributeImpl.h
@@ -178,7 +178,7 @@
 
   unsigned getAlignment() const;
   unsigned getStackAlignment() const;
-  std::string getAsString(bool InAttrGrp) const;
+  std::string getAsString(bool TargetIndependent, bool InAttrGrp) const;
 
   typedef SmallVectorImpl<Attribute>::iterator       iterator;
   typedef SmallVectorImpl<Attribute>::const_iterator const_iterator;