Using a recursive invocation of clearmake

Understand the advantage of using a recursive invocation of clearmake.

You can eliminate the problem of different build scripts described in Handling targets built in multiple ways by adding a recursive invocation of clearmake to the makefile in app_src:

../util_src/test_prog_3: ...
cd ../util_src ; $(MAKE) test_prog_3
Note: In this script example, $(MAKE) invokes clearmake recursively.

Now, the target test_prog_3 is built the same way in both directories. You can turn on build-script comparison again, by removing the .NO_CMP_SCRIPT special target.