Honor __unaligned in codegen for declarations and expressions

This patch honors the unaligned type qualifier (currently available through he
keyword __unaligned and -fms-extensions) in CodeGen. In the current form the
patch affects declarations and expressions. It does not affect fields of
classes.

Differential Revision: https://reviews.llvm.org/D30166

llvm-svn: 297276
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index bad963b..5f793f8 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -149,6 +149,8 @@
       Alignment = CGM.getClassPointerAlignment(RD);
     } else {
       Alignment = getContext().getTypeAlignInChars(T);
+      if (T.getQualifiers().hasUnaligned())
+        Alignment = CharUnits::One();
     }
 
     // Cap to the global maximum type alignment unless the alignment