First small part of lib cleanup. Mainly "constification" of arguments and
adding FIXME's.
diff --git a/lib/network.c b/lib/network.c
index d105db4..e1f733c 100644
--- a/lib/network.c
+++ b/lib/network.c
@@ -50,7 +50,7 @@
 
 /* Write nbytes from ptr to fd. */
 int
-writen(int fd, u_char *ptr, int nbytes)
+writen(int fd, const u_char *ptr, int nbytes)
 {
   int nleft;
   int nwritten;