Fix FTBFS on NetBSD: Don't use reserved keyword 'bool' as variable name.

Legacy code, from before 'bool' became a reserved keyword in the C standard.

Signed-off-by: Joachim Nilsson <joachim.nilsson@westermo.se>
config.mk: Update with details FreeBSD 9.2, NetBSD 6.1.2, and OpenBSD 5.4

Now pimd has been tested successfully on the following BSD variants, as
well as Linux:

* FreeBSD 9.2,
* NetBSD 6.1.2, and
* OpenBSD 5.4

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>