Revert "Remove -fopenacc command line option (llvm#187)" (llvm#197)

This reverts commit 8902936.

Author: ronlieb

clang/include/clang/Driver/Options.td

@@ -1472,7 +1472,7 @@ def fno_hip_emit_relocatable : Flag<["-"], "fno-hip-emit-relocatable">,
 // Clang specific/exclusive options for OpenACC.
 def openacc_macro_override
     : Separate<["-"], "fexperimental-openacc-macro-override">,
-      Visibility<[]>,
+      Visibility<[ClangOption, CC1Option]>,
       Group<f_Group>,
       HelpText<"Overrides the _OPENACC macro value for experimental testing "
                "during OpenACC support development">;
@@ -3664,8 +3664,10 @@ def fno_openmp_target_debug : Flag<["-"], "fno-openmp-target-debug">;
 //===----------------------------------------------------------------------===//
 // FlangOption + FC1 + ClangOption + CC1Option
 //===----------------------------------------------------------------------===//
-def fopenacc : Flag<["-"], "fopenacc">, Group<f_Group>, Visibility<[]>,
+let Visibility = [FC1Option, FlangOption, CC1Option, ClangOption] in {
+def fopenacc : Flag<["-"], "fopenacc">, Group<f_Group>,
   HelpText<"Enable OpenACC">;
+} // let Visibility = [FC1Option, FlangOption, CC1Option, ClangOption]
 
 //===----------------------------------------------------------------------===//
 // Optimisation remark options