Fix build by using hasFlag instead of hasArg.

llvm-svn: 261782
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 0206281..0cb49af 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -4270,8 +4270,8 @@
     CmdArgs.push_back("-ffunction-sections");
   }
 
-  if (Args.hasArg(options::OPT_fwhole_program_vtables,
-                  options::OPT_fno_whole_program_vtables, false)) {
+  if (Args.hasFlag(options::OPT_fwhole_program_vtables,
+                   options::OPT_fno_whole_program_vtables, false)) {
     if (!D.isUsingLTO())
       D.Diag(diag::err_drv_argument_only_allowed_with)
           << "-fwhole-program-vtables"