As a (mostly ignorable) sidenote, TCC does support a couple of non-intel ISAs. At least 4-5k LOC beween arm-gen.c and C67-gen.c, compiled from an IR https://github.com/LuaDist/tcc/blob/master/il-opcodes.h If this repository's anything to go by: https://github.com/LuaDist/tcc

I'm not sure how well maintained those backends are, and I've read TCC isn't really stable enough to use in production, between the incomplete x64 backend and just general bugs... Solving those may yet push TCC a fair bit beyond 60k LOC.