https://bugs.winehq.org/show_bug.cgi?id=58006
--- Comment #1 from Rafał Mużyło galtgendo@o2.pl --- Attach backtrace of the segfault.
Once you do, you'll see the problem lies in commit e3bf6e5e - the new check seems to be coming out of nowhere... (and would be sort of invalid for this specific command line (no output_name in the first place))
Seems the check was moved from build() to main() for some reason...