Silence some warnings produced by Clang, and add a missing header

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@89051 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/JumpDiagnostics.cpp b/lib/Sema/JumpDiagnostics.cpp
index a8e31d2..2b37e9d 100644
--- a/lib/Sema/JumpDiagnostics.cpp
+++ b/lib/Sema/JumpDiagnostics.cpp
@@ -325,5 +325,5 @@
 }
 
 void Sema::DiagnoseInvalidJumps(Stmt *Body) {
-  JumpScopeChecker(Body, *this);
+  (void)JumpScopeChecker(Body, *this);
 }