> See my follow up, that's not a complete solution either because the ...
Yup. I know didn't test it on enough systems, and that's why I left it at my "drafts" branch, and haven't submitted it to mob.
> way to find out which directory is used by gcc when calling without
> options (i.e. the default) is to inspect the output of
> % gcc --print-file-name=crt1.o
Assuming that's correct and we'd want to use that, and in the interest of self hosting, I'd suggest that tcc itself would also report correct output of such invocation, such that if configure is invoked with --cc=tcc, it would still be able to find the lib dir correctly as if it was gcc.