fix some of the build process

[fbt]

I've attempted to fix the DESTDIR issue somewhat.

The only thing I can't seem to figure out is why does the install target of libudev-comat ignores DESTDIR, and that makefile is far too complex for me, it seems.

[fbt]

Basically, now installing all the targets aside from libudev-compat works as intended from a first glance, and even the example configs come out right.

[jcnelson]

Looks good. Merged!