configure: Add basic support for Haiku

For compatibility with BeOS, Haiku's error codes are negative whereas recent
POSIX versions require them to be positive. As spotted by François, some
parts of QEMU code rely on this, so use a mapper library to convert them
to positive ones.

Cc: François Revol <revol@free.fr>
Cc: Ingo Weinhold <ingo_weinhold@gmx.de>

Haiku has network functions in libnetwork.so. It doesn't ship libutil.so.

Signed-off-by: Andreas Färber <andreas.faerber@web.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
