I expect that Linux-x86 is probably fine. All other architectures
except ARM are definitely broken since I haven't yet implemented
gfunc_sret for these, although replicating the current behaviour
should be straightforward.
Only one test so far, which fails on Windows (with MinGW as the native
compiler - I've tested the MinGW output against MSVC and it appears the
two are compatible).
I've also had to modify tcc.h so that tcc_set_lib_path can point to the
directory containing libtcc1.a on Windows to make the libtcc dependent
tests work. I'm not sure this is the right way to fix this problem.
