how to reference the directory where current Makefile resides ?

[Yakov Lerner]

How can I reference the directory where the currently executed Makefile
resides (like what $(dirname $0) is in bash ) ?

Here is what I am trying to do:

1. In the same dir of Makefile, there is a "submakefile" that I need to
include ("include submakefile").

2. When my cwd is same where Makefile resides, then no problem:
'include submakefile' works.

3. But when I am in different dir, then make does not find the
submakefile. Is there any builtin variable for the directory of
the current Makefile (like `dirname $0` in shell) ?, so I can write
something line
          include $(DIR_OF_MAKEFILE)/submakefile
?

Thanks
Yakov