Fix utf8_to_uvchr for non-core calls

Commit a460925186154b270b7a647a4f30b2f01fd97c4b broke calling this and
related functions from outside of core Perl, but only when the input is
empty (which is an error anyway, so was not caught except for deliberate
API edge case tests in Devel::PPPort).

1 files changed, 6 insertions, 1 deletions

diff --git a/inline.h b/inline.h
index c2123ad096..c5f0ee69b3 100644
--- a/inline.h
+++ b/inline.h
@@ -2468,7 +2468,12 @@ Perl_utf8n_to_uvchr_msgs(const U8 *s,
      * cases. */
 
     /* No calls from core pass in an empty string; non-core need a check */
-    PERL_NON_CORE_CHECK_EMPTY(s, send);
+#ifdef PERL_CORE
+    assert(curlen > 0);
+#else
+    if (curlen == 0) return _utf8n_to_uvchr_msgs_helper(s0, 0, retlen,
+                                                        flags, errors, msgs);
+#endif
 
     type = PL_strict_utf8_dfa_tab[*s];