When redirection operators are included in a command string passed to
the system() subroutine, it spawns an intermediate shell to handle the
redirection. This is particularly inefficient when running the tests
in MSYS2. Creating our own version of system() based on fork() and
exec() allows us to handle the redirection directly.
By adding ivtest to the iverilog source tree, it is easier to keep
the regression test synchronized with the source that is being tested.
This should be especially helpful for PRs that add a new feature, and
have a matching ivtest PR with the regression test for that feature.
Martin Whitaker
Cary R
Stephen Williams