29.3 Recursive Execution of Make

We recurse into subdirectories by calling MAKE in each directory that appears in the variable DIRS. The variable DIRS is assumed to contain just the next level subdirectories, i. e., there should be no / character in the value of DIRS. Otherwise the SUBMAKE code will not work. We do not assume that the subdirectories already contain a Makefile. It should, however, be possible to generate in each subdirectory a Makefile from Makefile.nw. Since the following SUBMAKE should also work when included in a Makefile in some deep subdirectory, we have to make sure that the variable PROJECTROOT points to the root of the project’s tree.