The conffiles definition in Makefile should not contain leading whitespace.
Remove whitespace from Makefile of motion, dnscrypt-proxy and sstp-client.

Reference to discussion at #2652

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>

- Ship a `net/ppp_defs.h` replacement header since musl does not provide one
   but `pppd/pppd.h` provided by pppd is needing it.
 - Add missing `sys/types.h` includes

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>

Signed-off-by: Federico Di Marco <fededim@gmail.com>

Signed-off-by: Federico Di Marco <fededim@gmail.com>