> Parts of src/lib/goa/allegro/misc.cpp seem to have been written with the assumption that only Windows and MacOS would be supported. e.g. on line 41,

Ah, I think that's a quick hack that got left in. I think it'll work if you just do some commenting or #ifdef:ing out.

> then I'd have to also mirror their entire (quite large) source code, due to the LGPL

I don't think that is the case for distribution of unmodified binaries. I'm no expert on the GPL, though, but I recall that you don't need to distribute the source if it's available and you didn't modify it.