[perl #79824] Don’t cow for sv_mortalcopy call from XS

XS code doing sv_mortalcopy(sv) will expect to get a true copy, and
not a COW ‘copy’.

So make sv_mortalcopy and wrapper around the new sv_mortalcopy_flags
that passes it SV_DO_COW_SVSETSV, which is defined as 0 for XS code.

1 files changed, 7 insertions, 0 deletions

diff --git a/mathoms.c b/mathoms.c
index 7f498636cb..a29f70ca11 100644
--- a/mathoms.c
+++ b/mathoms.c
@@ -93,6 +93,7 @@ PERL_CALLCONV UV Perl_to_utf8_lower(pTHX_ const U8 *p, U8* ustrp, STRLEN *lenp);
 PERL_CALLCONV UV Perl_to_utf8_title(pTHX_ const U8 *p, U8* ustrp, STRLEN *lenp);
 PERL_CALLCONV UV Perl_to_utf8_upper(pTHX_ const U8 *p, U8* ustrp, STRLEN *lenp);
 PERL_CALLCONV UV Perl_to_utf8_fold(pTHX_ const U8 *p, U8* ustrp, STRLEN *lenp);
+PERL_CALLCONV SV *Perl_sv_mortalcopy(pTHX_ SV *const oldstr);
 
 /* ref() is now a macro using Perl_doref;
  * this version provided for binary compatibility only.
@@ -1202,6 +1203,12 @@ Perl_to_utf8_upper(pTHX_ const U8 *p, U8* ustrp, STRLEN *lenp)
     return _to_utf8_upper_flags(p, ustrp, lenp, FALSE, NULL);
 }
 
+SV *
+Perl_sv_mortalcopy(pTHX_ SV *const oldstr)
+{
+    Perl_sv_mortalcopy_flags(aTHX_ oldstr, SV_GMAGIC);
+}
+
 END_EXTERN_C
 
 #endif /* NO_MATHOMS */