small bug in stty

[Harry Liu]

Without POSIXLY_CORRECT set, "stty erase -" (found in a script that meant to do
"stty erase ^-") causes stty to segfault.  One line patch for sh-utils-2.0
below.

--- sh-utils-2.0/src/stty.c~    Sun Mar 28 19:12:17 1999
+++ sh-utils-2.0/src/stty.c     Tue Jun 20 20:33:32 2000
@@ -671,7 +671,7 @@
 {
   char ch;
 
-  if (*opt++ != '-')
+  if (*opt++ != '-' || *opt == 0)
     return 0;
 
   while ((ch = *opt))