ifplugd: move linux header inclusion after userspace headers

this allows linux' new libc-compat.h to kick in, which prevents
redefinition of some structs that both userspace and kernel
headers define. without this patch, struct ethhdr gets redefined
and breaks the build against musl libc.

Signed-Off-By: John Spencer <maillist-busybox <at> barfooze.de>
mount: remove uclibc ifdef message
ntpd: add a delayed retry to resolve hostname
date: add missing -k flag
arping: add missing includes
netmsg: new applet
lock: new applet