PATCH: computil.c segfaults when _values called with too few arguments

[Travis Spencer <tspencer@cs.pdx.edu>]

Given this completion definition:

#compdef testvalues

_arguments "-n:foo bar:_values -s , -S ''"

After entering the `-n' flag and then hitting tab, zsh will segfault
every time as demonstrated in the following typescript:

Script started on Mon Jul 11 01:05:49 2005
murzim% stash/opt/bin/zsh -f
murzim% fpath=( .zsh/functions $fpath )
murzim% autoload compinit
murzim% compinit
murzim% testvalues -n zsh: segmentation fault (core dumped)  stash/opt/bin/zsh -f
murzim% exit

script done on Mon Jul 11 01:06:38 2005
Script started on Mon Jul 11 01:54:21 2005
murzim% stash/opt/bin/zsh --version
zsh 4.3.0-dev-1 (sparc-sun-solaris2.9)
murzim% exit

script done on Mon Jul 11 01:54:46 2005

The problem was caused by dereferencing a NULL pointer in parse_cvdef.
Here is a patch to fix the problem.

Index: Src/Zle/computil.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/Zle/computil.c,v
retrieving revision 1.88
diff -u -p -r1.88 computil.c
--- Src/Zle/computil.c	7 Dec 2004 16:55:12 -0000	1.88
+++ Src/Zle/computil.c	11 Jul 2005 08:58:06 -0000
@@ -2660,7 +2660,8 @@ parse_cvdef(char *nam, char **args)
     char **oargs = args, sep = '\0', asep = '=', *name, *descr, *p, *q, **xor, c;
     int xnum, multi, vtype, hassep = 0, words = 0;
 
-    while (args[0][0] == '-' &&
+    while (args && args[0] && args[1] &&
+           args[0][0] == '-' &&
            (args[0][1] == 's' || args[0][1] == 'S' || args[0][1] == 'w') &&
            !args[0][2]) {