Add support for Microsoft's __thiscall, from Steven Watanabe!

llvm-svn: 104026
diff --git a/clang/lib/Frontend/PCHReaderDecl.cpp b/clang/lib/Frontend/PCHReaderDecl.cpp
index 49010bf..1e8bd2f 100644
--- a/clang/lib/Frontend/PCHReaderDecl.cpp
+++ b/clang/lib/Frontend/PCHReaderDecl.cpp
@@ -763,6 +763,7 @@
     UNSIGNED_ATTR(Regparm);
     STRING_ATTR(Section);
     SIMPLE_ATTR(StdCall);
+    SIMPLE_ATTR(ThisCall);
     SIMPLE_ATTR(TransparentUnion);
     SIMPLE_ATTR(Unavailable);
     SIMPLE_ATTR(Unused);