Supply the header corresponding to a library builtin as a separate argument to the LIBBUILTIN macro

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64676 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index b194c9e..5d02b66 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -315,7 +315,7 @@
     Diag(Loc, diag::ext_implicit_lib_function_decl)
       << Context.BuiltinInfo.GetName(BID)
       << R;
-    if (!Context.BuiltinInfo.getHeaderName(BID).empty() &&
+    if (Context.BuiltinInfo.getHeaderName(BID) &&
         Diags.getDiagnosticMapping(diag::ext_implicit_lib_function_decl)
           != diag::MAP_IGNORE)
       Diag(Loc, diag::note_please_include_header)