ps: add catastrophic_failure()

The catastrophic_failure function tries to make bug reporting useful
by telling in which line error occured, and drops core.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

ps/common.h

@@ -334,6 +334,8 @@ extern void do_help(const char *opt, int rc) NORETURN;
 
 /* global.c */
 extern void self_info(void);
+extern void catastrophic_failure(const char *filename, unsigned int linenum,
+				 const char *message);
 
 /* parser.c */
 extern int arg_parse(int argc, char *argv[]);