Make warn treat $@=3 and $@="3" the same

If we get this:

$ ./perl -Ilib -e '$@ = "3"; warn'
3	...caught at -e line 1.

then we shouldn’t get this:

$ ./perl -Ilib -e '$@ = 3; warn'
Warning: something's wrong at -e line 1.

as the two scalars hold the same value.

1 files changed, 1 insertions, 1 deletions

diff --git a/pp_sys.c b/pp_sys.c
index 994bd6ce9c..79ef266c7f 100644
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -453,7 +453,7 @@ PP(pp_warn)
 	}
 	else exsv = ERRSV;
       }
-      else if (SvPOKp(ERRSV) && SvCUR(ERRSV)) {
+      else if (SvPOKp(ERRSV) ? SvCUR(ERRSV) : SvNIOKp(ERRSV)) {
 	exsv = sv_newmortal();
 	sv_setsv_nomg(exsv, ERRSV);
 	sv_catpvs(exsv, "\t...caught");