add CI

[stsp]

Hi Andrew, would you like to add CI
for that?
The idea is to build hello_asm demo,
dosemu2 and comcom64, and check
that everything works together.

If the pushed changes are so incompatible
that even comcom64 or dosemu2 should
be source-patched, then I'll have to do
skip_ci to push those 2 later.