PATCH: untokenize string sent to matheval for (#) flag

Fixes 49409.
---

Before:
echo ${(X#):-2#1011010}
zsh:1: bad math expression: illegal character: ^?

After:
echo ${(X#):-2#1011010}
Z

I don't think matheval ever does anything useful with tokenized strings so this
shouldn't cause any problems, right?

 Src/subst.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Src/subst.c b/Src/subst.c
index 1776d5e164..9c7ba6c453 100644
--- a/Src/subst.c
+++ b/Src/subst.c
@@ -1494,6 +1494,8 @@ substevalchar(char *ptr)
     int saved_errflag = errflag;
 
     errflag = 0;
+    ptr = dupstring(ptr);
+    untokenize(ptr);
     ires = mathevali(ptr);
 
     if (errflag) {  /* not a valid numerical expression */
-- 
2.38.1