speed up feature-checking slightly

When seeing whether the cop hint hash contains the given feature,
Perl_feature_is_enabled only needs to see whether the hint hash ele-
ment exists.  It doesn’t need to turn it into a scalar.

1 files changed, 3 insertions, 0 deletions

diff --git a/hv.h b/hv.h
index e45460a8c0..05245d58a7 100644
--- a/hv.h
+++ b/hv.h
@@ -509,6 +509,9 @@ struct refcounted_he;
 
 /* flags for the refcounted_he API */
 #define REFCOUNTED_HE_KEY_UTF8		0x00000001
+#ifdef PERL_CORE
+# define REFCOUNTED_HE_EXISTS		0x00000002
+#endif
 
 #ifdef PERL_CORE