Nested make

[Hridyesh Pant]

I got below good query in Net but not able to get answer, could anyone suggest 
what will be the workaround for below situation?

Question:
I have a need to create a project-wide set of makefiles that will do the 
following:

given a set of applications under one project: 
-project/
   makefile
   app1/
       makefile
             src/
                 makefile?
             bin/
   app2/
       makefile
             src/
             bin/

The need is to create a makefile set that when in the application directory, 
make will make the application and when running make from the project 
directory, the whole project will be built. 

It would be nice if the makefile at the project level could be dynamic - be 
able to find all directories under it and descend into then to execute the 
makefile there. I think the way to start that would be to be able to assign the 
output of a command (find . -type d -print) to a make variable. I don't know 
how to do that either. 

Thanks
Hridyesh