PANICTRACE (stacktrace on panic or signal) + bits

On crash signal or panic(), use a configurable method to get a stacktrace
the user can easily report to us.  Currently only for Unix/Linux and only
ifdef BETA.  Hopefully ports can add additional methods.

Bits:
- linux hints file had PREFIX definition in the wrong place
- sample sysconf file used wrong delimiter for WIZARDS
- fix grammar error in support message when using sysconf.wizards
- options.c comment typo
- capitalize "Crash test" output from #panic command

src/decl.c

@@ -326,6 +326,10 @@ NEARDATA struct savefile_info sfrestinfo, sfsaveinfo = {
 #endif
 };
 
+#ifdef PANICTRACE
+char *ARGV0;
+#endif
+
 /* dummy routine used to force linkage */
 void
 decl_init()