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/NewInstall.unx

@@ -31,6 +31,9 @@ If you are using the traditional configuration system, see Install.unx.
 4. Install:
    Depending on your configuration, this step may or may not need to be done
    as root; check the hints file.
+   NB: "make install" deletes nethackdir and recreates it from scratch - so
+   if you want the record, logfile, or sysconf files, you must save and
+   restore them manually.
 	cd $Top
 	make install