new: net/gblc

Hello OpenBSD-Team,

I've made a new port for the tool gblc. Gude is a manufacturer of network
devices like powerswitches. The gblc (Gude Boot Loader Client) utility
can be used to search GBL devices within your network, to modify their network
settings, perform a reset to factory defaults or to update the firmware.

For this port to work, I created the Makefile for correct usage of gnu autoconf
and automake, adjusted the source code via patches for OpenBSD, fixed several
existing c-compiler errors and warnings and tested the tool.

Source homepage and informations: https://wiki.gude-systems.com/HOWTO_gblc

Please test the port. I'd appreciate any comments.

Regards,
Timo