Throughout Cygwin, use u_intN_t or uintN_t

Don't use u_char, u_short, u_int or u_long in Cygwin, unless it refers
to the Winsock types.  Use u_intN_t in BSD-based sources, unsigned char
where strings are concerned, uintN_t otherwise.  Also:

	* net.cc: Fix comment, we're not using u_long anymore.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

winsup/cygwin/libc/arc4random_stir.c

@@ -19,6 +19,6 @@ arc4random_stir(void)
 }
 
 void
-arc4random_addrandom(u_char *dat, int datlen)
+arc4random_addrandom(u_int8_t *dat, int datlen)
 {
 }