Setting up toolchains

[Anthony Webber <akwebber@reckeng.com>]

Please excuse the naivety of this question, but I've looked elsewhere 
and can't find a good answer. Perhaps a good answer is to install MSYS2 
alongside Cygwin.

Anyway, I am trying to set up my gcc toolchains in Cygwin, by which I 
mean that I'm trying to set up the environment so that the right 
programs are called at the right time by build systems like cmake and 
waf, or if I want to build in a more manual fashion. Particularly, I 
want to be able to switch between toolchains easily.

I have installed both the x86_64-pc-cygwin-gcc/g++ and 
x86_64-w64-mingw32-gcc/g++ packages using setup-x86_64.exe.

The first thing I notice is that the gcc/g++ programs in /bin are 
identical to  x86_64-pc-cygwin-gcc/g++, and that symbolic links aren't 
being used. I presume it's being done this way because this is 
considered the default, native Cygwin toolchain, and that there should 
be be relatively little to do in the way of configuration if I want to 
build Cygwin software.

If I do want to cross-compile using x86_64-w64-mingw32-gcc/g++, then I 
imagine that the very least I should do is set a bunch of environment 
variables like CC and CXX (perhaps by sourcing a shell script), but 
really I'd like some advice here. What do you guys do?