in 0.4.6 the configure script does not add "-lz" (zlib) for some reason. make will fail as there are unknown references. when -lz is manually added to xournal_LDADD in the makefile it works fine. i don't know if you want to do something about that, but this info should help people facing the same problem.
Good to know… I thought the line
LDFLAGS="$LDFLAGS -lz -lm"
in configure.in would take care of it (on at least some Linux distros it does), but I guess not…