@aspragg @conservancy @theregister I can't remember when I've hit proprietary tool chain dependencies, it certainly isn't very often.
My bigger issue is about versions - I still run into a lot of stuff that uses Python 2.7 and many distros have tried to root out Python 2.7 root and branch - and rebuilding that and its packages can be a pain. And then I run into "small" differences that aren't really small like gmake vs Unix make or Cmake (or Unix sh vs bash). And sometimes the configuration settings for a package (like the Linux kernel) need to be "just so". Perhaps the toolchain dependency that has driven me most crazy is openssl.