PR4836, part 1: add Sema support for __builtin_isnan and friends; they 
are apparently used by Solaris libc despite the fact that clang claims 
to be compatible with gcc 4.2, which doesn't support them.

llvm-svn: 80610
diff --git a/clang/lib/Sema/Sema.h b/clang/lib/Sema/Sema.h
index f9c893f..2a2515f 100644
--- a/clang/lib/Sema/Sema.h
+++ b/clang/lib/Sema/Sema.h
@@ -3494,6 +3494,7 @@
                                                     CallExpr *TheCall);
   bool SemaBuiltinVAStart(CallExpr *TheCall);
   bool SemaBuiltinUnorderedCompare(CallExpr *TheCall);
+  bool SemaBuiltinUnaryFP(CallExpr *TheCall);
   bool SemaBuiltinStackAddress(CallExpr *TheCall);
 
 public: