By popular request reinstate fakeidentd's standalone mode.

Since this is also needed for other applets like telnetd,
introduce generic driver for such things.
It even supports inetd-wait ('linger') mode, when inetd
hands out listen socket to child and waits to it to die,
instead of handing out accepted socket and continuing
listening itself (nowait mode).
Code growth ~200 bytes.
NB: our inetd doesn't support wait mode yet (or mabe it is buggy).

include/usage.h

@@ -826,22 +826,16 @@
        "\\( and \\) or null; if \\( and \\) are not used, they return the number\n" \
        "of characters matched or 0."
 
-#if 0 /* bloaty */
 #define fakeidentd_trivial_usage \
-       "[-b ip] [STRING]"
+       "[-fiw] [-b ADDR] [STRING]"
 #define fakeidentd_full_usage \
-       "Return a set string to auth requests" \
-       "\n\nOptions:\n" \
-       "	-b	Bind to ip address\n" \
-       "	STRING	The ident answer string (default is nobody)"
-#else /* inetd-only */
-#define fakeidentd_trivial_usage \
-       "[username]"
-#define fakeidentd_full_usage \
-       "Return a (faked) ident response.\n" \
-       "This applet is meant to run from inetd.\n" \
-       "Optional argument is the username to return (default is 'nobody')."
-#endif
+       "Provide fake ident (auth) service" \
+       "\n\nOptions:" \
+       "\n	-f	Run in foreground" \
+       "\n	-i	Inetd mode" \
+       "\n	-w	Inetd 'wait' mode" \
+       "\n	-b ADDR	Bind to specified address" \
+       "\n	STRING	Ident answer string (default is 'nobody')"
 
 #define false_trivial_usage \
        ""