Heck, badwolf just works unmodified, just had to not have -g in CFLAGS due to --gdwarf-5 being an unrecognised option by the as called by Haiku's gcc (weird).
Also had to pick pkgconf in the package manager because the pkg-config I first ended up with (I guess it's the freedesktop one…) doesn't supports the --atleast-version= option.
@lanodan Now try porting it to Windows. (You can cheat by compiling it on ReactOS)
After all POSIX just ends up everywhere and Microsoft themselves had to make a compat layer otherwise US Federal Government wouldn't have accepted Windows. ( https://en.wikipedia.org/wiki/Microsoft_POSIX_subsystem )