Move set_cap() to ncmlib/cap.[ch].

ifchd/linux.h

@@ -1,5 +1,5 @@
 /* linux.h - ifchd Linux-specific functions include
- * Time-stamp: <2010-11-12 04:59:01 njk>
+ * Time-stamp: <2010-11-12 09:03:29 njk>
  *  
  * (C) 2004 Nicholas J. Kain <njk@aerifal.cx>
  *
@@ -31,6 +31,5 @@ void perform_subnet(int idx, char *str);
 void perform_router(int idx, char *str);
 void perform_mtu(int idx, char *str);
 void perform_broadcast(int idx, char *str);
-void set_cap(uid_t uid, gid_t gid, char *captxt);
 #endif