implement ast building and trivial semantic analysis of stmt exprs.
This implements test/Sema/stmt_exprs.c



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@40465 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Sema/Sema.h b/Sema/Sema.h
index 39a3cc0..e1857b7 100644
--- a/Sema/Sema.h
+++ b/Sema/Sema.h
@@ -271,6 +271,9 @@
   virtual ExprResult ParseAddrLabel(SourceLocation OpLoc, SourceLocation LabLoc,
                                     IdentifierInfo *LabelII);
   
+  virtual ExprResult ParseStmtExpr(SourceLocation LPLoc, StmtTy *SubStmt,
+                                   SourceLocation RPLoc); // "({..})"
+  
   /// ParseCXXCasts - Parse {dynamic,static,reinterpret,const}_cast's.
   virtual ExprResult ParseCXXCasts(SourceLocation OpLoc, tok::TokenKind Kind,
                                    SourceLocation LAngleBracketLoc, TypeTy *Ty,