Delete the CORE/prevailing_version key from the hint hash inside stri…

…ng eval so perl code doesn't get to see it

pp_ctl.c

@@ -4077,11 +4077,18 @@ S_doeval_compile(pTHX_ U8 gimme, CV* outside, U32 seq, HV *hh)
             SvREFCNT_dec(GvHV(PL_hintgv));
             GvHV(PL_hintgv) = hh;
             FETCHFEATUREBITSHH(hh);
-            SV *versv, **svp;
-            if((svp = hv_fetchs(hh, "CORE/prevailing_version", 0)) && (versv = *svp) && SvOK(versv)) {
+            /* temporarily turn magical flags off so we can delete without it getting in the way */
+            const U32 wasflags = SvFLAGS(hh);
+            SvMAGICAL_off(hh);
+
+            SV *versv;
+            /* hh is a new copy for us to use; we are permitted to delete keys */
+            if((versv = hv_deletes(hh, "CORE/prevailing_version", 0)) && SvOK(versv)) {
                 SAVEI16(PL_prevailing_version);
                 PL_prevailing_version = SvUV(versv);
             }
+
+            SvFLAGS(hh) = wasflags;
         }
     }
     SAVECOMPILEWARNINGS();