Do not attempt to install ircDDBGatewayConfig when using GUI-less
Makefile. ircDDBGatewayConfig is a GUI application and regular
Makefile does not build it.
Removes any GUI related dependencies from the Makefile
that is intended to build only console (GUI-less)
applications.
As a result developers can just install wxGTK-base-dev
to compile a solution on embedded devies instead of
a full wxGTK-dev that weights a ton.
Introduces a `BUILD` make parameter to allow for building both debug
and release variants from the same Makefile. This also makes the
Makefile-defined preprocessor macros more in line with those from
Visual Studio build.
Minor changes:
* allows for overwriting LOGDIR, CONFDIR, BINDIR and DATADIR from
command line (make parameter)
* converts BUILD to Markdown for better visibility on Github
* improves Linux build instructions in BUILD.md