I'm a big fan of capturing the toolchain(s) with the repo. I have had to hack this for embedded toolchains out of necessity for years (decades?) using VirtualBox on a Mac. I still have a Windows 95 VM sitting around containing a copy of Keil or something that is the only known way to rebuild the code for a certain weird-ass micro from some consulting gig in the late 90's. I wonder if it still boots? Hopefully, that customer forgot about me...