Also removed the lib-dir merging with sysdep. Updated #include's
accordingly.
Fixed make doc on recent Debian together with moving generated doc into
objdir.
Moved Makefile.in into root dir
Retired all.o and birdlib.a
Linking the final binaries directly from all the .o files.
Note that this is (and always was) a terrible hack and we really should
replace it with something reasonable which wouldn't need changing every
time linuxdoc-tools evolve.
I also needed to include a patched version of LinuxDocTools.pm, because the
original one explicitly refused to work with a non-linuxdoc DTD. The authors
of linuxdoc recommend to use sgmltools-lite in such cases, but it would mean
rewritting our formatting rules to the DSSSL language which I don't dare to
speak about here :)
