This builds a set of packages from xbps-packages using xbps-src -- while taking
into account inter-dependencies between all of the packages in the set.

It gets a list of pkgs that need to be rebuilt from running:

	xbps-checkvers

Then, it finds all of the dependencies of each package in the list and adds
Make rules for them, if those dependencies are in the same list.

To use it, type:

	./configure

This generates a 'repo-checkvers.txt' file with the output of 'xbps-checkvers'.

If you run this again, it will have no effect until you delete that txt file, or
change the repo-checkvers.txt file to have a different set than it did before.

Builds can be interrupted and resumed, because a full list of packages that need
to be built are contained in small files that Make looks for to satisfy its
targets in the generated "tobuild" subdirectory.  Once a package has been built,
a small file is created into the "built" subdirectory in order to tell Make not
to build it again.

Every time you run './configure', those two subdirectories are reset, so you
cannot interrupt a build, run './configure', and resume properly.  In order to
resume a build in these kinds of circumstances, you must completely remove
'repo-checkvers.txt', so that ./configure can detect what has already been
built.

After you have the set that you want, a 'Makefile' is generated.  To begin
building, type 'make'.

See the end of the Makefile for additional targets other than 'all'.

Questions?  Ask at #xbps on irc.freenode.net!  NO WARRANITES!