SHELLERS for SYSCF, MacOS 10.5 hints file (trunk only)

Add SHELLERS - people allowed to use ! command with same syntax as WIZARDS.
Add new hints file for 10.5, since the rules and commands for groups changed
(new commands introduced in 10.4, old ones removed in 10.5; creating a new
user under 10.4 gave you a matching group, in 10.5 it doesn't).  Also move
shared build into roughly right place in file system when being installed
for root - don't use ~root.
Makefile.top - don't remove ./-p unless it exists (that's always annoyed me).
fix error invoking macosx.sh

include/sys.h

@@ -13,6 +13,7 @@ struct sysopt {
 	char *support;	/* local support contact */
 	char *recover;	/* how to run recover - may be overridden by win port */
 	char *wizards;
+	char *shellers;	/* like wizards, for ! command (-DSHELL) */
 	int   maxplayers;
 };
 E struct sysopt sysopt;