V0.99i - re-implement "make DESTDIR=<path> install"
Created by: cjashfor
Change the way "make DESTDIR= install" works so that all needed artifacts are installed into the DESTDIR. See the commit comments for details.
Most implementations of "make install" will also install docs, but this feature isn't implemented yet, and it's not clear how to do that since the documentation is not in a standard format.