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.

include/sys.h

@@ -15,6 +15,11 @@ struct sysopt {
 	char *wizards;
 	char *shellers;	/* like wizards, for ! command (-DSHELL) */
 	int   maxplayers;
+		/* record file */
+	int persmax;
+	int pers_is_uid;
+	int entrymax;
+	int pointsmin;
 };
 E struct sysopt sysopt;