A little help for clang++ in toke.c

This was failing to compile with Apple LLVM version 6.0 like so:

toke.c:6558:13: error: no member named 'Perl_rv2cv_op_cv' in 'gv';
                       did you mean simply 'Perl_rv2cv_op_cv'?
                                : (CV *)gv
                                        ^~

1 files changed, 1 insertions, 1 deletions

diff --git a/toke.c b/toke.c
index 8585b7ab1e..aeaeb46254 100644
--- a/toke.c
+++ b/toke.c
@@ -6555,7 +6555,7 @@ Perl_yylex(pTHX)
 			    ? GvCV(gv)
 			    : SvROK(gv) && SvTYPE(SvRV(gv)) == SVt_PVCV
 				? (CV *)SvRV(gv)
-				: (CV *)gv
+				: ((CV *)gv)
 			: rv2cv_op_cv(rv2cv_op, RV2CVOPCV_RETURN_STUB);
 		}