kati does not support --include-dir option. Therefore if a makefile needs to include other makefiles, full path needs to be specified with include directive. For example,
include test/mytest.mk

With --include-dir option supported as below, kati will search mytest.mk file under test directory.
$ ckati --include-dir test

Then include directive only needs to specify included file not full path to the file as below.
include mytest.mk