Add recordfile control to SYSCF.

Add sys/unix/sysconf, a sample sysconf file.
Move defines from topten.c to config.h so they can be seen globally.
Add persmax, pers_is_uid, entrymax, and pointsmin to struct sysopt, use
 in topten.c, populate in files.c
Warning cleanup in files.c.
BUGFIX: don't crash in unixmain.c if WIZARDS left unspecified.
hints/macosx10.5: don't hardcode "keni"; install sample sysconf; install
 sample ~/nethackrc
makedefs: add "system configuration" to compiled-with options list.
BUGFIX: if a game doesn't meet the criteria for making the record file it's
 shown to the user as having zero points because t1->points is set to zero
 to indicate that it doesn't get written back; display u.urexp instead.

sys/unix/unixmain.c

@@ -549,7 +549,7 @@ authorize_wizard_mode()
 #ifdef WIZARD
 	struct passwd *pw = get_unix_pw();
 #ifdef SYSCF
-	if (pw && sysopt.wizards[0]) {
+	if (pw && sysopt.wizards && sysopt.wizards[0]) {
 	    if(check_user_string(sysopt.wizards)) return TRUE;
 	} else
 #endif