Change behavior for the network-address and broadcast-address.
Users should not specify such addresses, but if they do, generate
something more sensible.
Also, if the address was in network larger then /24, the
generated address range was rather unexpected. Change behavior
here.
There are no particularly strong reasons for the chosen range.
It just seems suitable. The decision to hand out at most a /24
is because it is likely to be plenty, and because that is what
the previous code did -- at least, if the address was in the
first /24 of the subnet. See how the result for 192.168.0.1/20
is unchanged, but 192.168.1.1/20 changes.
Keep the include paths clean and separate. We use directories to group source
files together. That makes sense (I guess), but then we should use this
grouping also when including files. Thus require to #include files with their
path relative to "src/".
Also, we build various artifacts from the "src/" tree. Instead of having
individual CFLAGS for each artifact in Makefile.am, the CFLAGS should be
unified. Previously, the CFLAGS for each artifact differ and are inconsistent
in which paths they add to the search path. Fix the inconsistency by just
don't add the paths at all.
