This adds completions when building with readline. kamiftp now completes command name, special arguments (on/off), local paths (default readline behaviour) and remote paths. This also tells readline how to handle quotes and escape characters.

fixes `make distcheck'. it's so GNU to not ship manpages by default :/

I talked too fast. There's a typo that disabled readline even if found with pkg-config, and also the way I hooked it in kamiftp was wrong...

It's incredible how hard is to find an optional dependency that's needed only for some targets. I don't want to use a subdir because kamiftp needs the whole compat stuff as everything else, damn!

Trying to maintain two branches was impossible at this stage for me alone, so I'll recognize my stupidity and merge the portable branch into the main one. The repository will build using autotools.