The added change in MACHDEP (configure.ac) makes sys.platform return plain haiku, instead of haiku1 in beta5, or haikuR1~beta5+develpment on nightlies.
This makes it more aligned with what's done for Linux and FreeBSD, where it returns just the name in lower case, and no version suffix.
ToDo: clean up the rest of patchsets, where we used: if sys.platform.starswith("haiku"), or sys.platform[:5] == "haiku".
Build tested on hrev59595, x86_64.
c6a86dc1c3