> $ portlint -C
> WARN: /disk-samsung/freebsd-ports/security/kuku/pkg-plist: You have defined USE_LDCONFIG, but this port does not install shared objects in the format lib*.so.[0-9] which ldconfig(8) needs to register them in the hints file.
> 0 fatal errors and 1 warning found.
This port installs:
therefore USE_LDCONFIG is needed.
What does pkg-plist say?
IOW are those libraries listed?
# make -DBATCH check-plist
(In reply to Chris Hutchinson from comment #1)
They are listed, there are no plist issues.
According to the ldconfig(8) man page, filenames must conform to the pattern "lib*.so.[0-9]", which these do not. And if you run ldconfig against these libraries, elf hints are not processed. The port needs to install libkuku.so.2 for ldconfig to properly process the library.
ldconfig(8) has been updated and doesn't contain the limitation "lib*.so.[0-9]" any more. 
There is another case when USE_LDCONFIG is always needed - when the directory is not lib.
Testcase where portlint complains when it shouldn't: audio/carla
Thanks, Yuri. Seems like ldconfig itself needs to be changed, at least in the list_elf_hints() function. It still enforces the old pattern and thus won't print those libraries. But that doesn't seem to affect the actual linker.
Fixed in 2.19.7.