Allows simplifying the Makefile. CMake patch is from upstream.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

This adds libnatpmp from old packages and updates it to version
20140401. This new version has to install the header file declspec.h.

libnatpmp is needed for tor.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>