#391 Cross compilation improvements

[Doron Behar]

Hello,

I'd like to suggest a few improvements for lirc to handle cross compilation better. The attached patches were tested with Nixpkgs, and seems to work for us (with a few changes to the Nix expression not published here).

Please consider merging at least some of them - many of them

[Sean Young]

Looks great! Applied.

[Doron Behar]

Thanks for the quick merge! I hope you tested it doesn't break anything for regular distros.