made it compliant to the GNU build system

[alkis05]

I now this is a simple program and it might be an overkill, but I was exercising the use of autotools. I took the libert to put a GLP COPYING file there, but it that wasn't your intention, fell free to change it or take it out. Maybe all of this will make it easier for people to package this tool to some distribution.

More specifically, I chanced the .c and .h files to src, made {.,src]/Makefile.am and configuure.ac, altered main.c to include the generated config.h, added a build directory and updated the installation instructions in README.md. Automake asks for the creation of certain files, so it has a generic INSTALL file a copy of GLP licence (COPYING) AND some empty files (NEWS,AUTHOR, ChangeLog, etc). As is standard, now the make file has new targets, namely: make install, make uninstall, make dist (creates a tarball) and make distclean.

By the way, thx for this tool. I'm making a custom pkg manager using overlay and this is going to make it a little bit easier to do it. This is my first pull request, so

[kmxz]

I'm actually not quite familiar with GNU build system. Give me some time to take a look into this PR. Thanks.

[mjeveritt]

Whilst this looks like quite a good PR, couple of observations:

• Looks like some autotools cache 'crap' has got caught in the PR (which some .gitignore probably should catch)
• Need a rebase - above shows some conflicts :slightly_frowning_face: