The new feature should be present in SVN revision 1174561 or higher. It will detect when libcarddav or libcaldav are not present and automatically deactivate the affected resource(s).
Not sure whether I understand correctly. I removed the libcaldav package and rebuilt kdepim. I have libical installed because I understood that the package is a requirement.
FTBFS. Log attached.
That is a strange error; I do not know what would cause it. Try without the -j4 flag (i.e. a single-core build) and see what happens.
Tim