I remember getting annoyed needing a windows driver that was part of an open source package. That needed autotools to build. I got annoyed trying to make it compile under mysys/MinGW. So I built a gcc cross compiler under linux. Compiled the damn driver and it just worked(tm).

by default it supports a variety of targets, you don't need to set it up.

setting up the system libraries is relatively easy, make a copy of the target you're building for, assuming it has a setup for compilation, and use --sysroot=/path/to/target.