Recursive make in subdirectories

Question

How can I order make command in the Makefile to execute recursively in all subdirectories make commands (defined in the Makefile in the subdirectories)

Answer 1

I will submit here my particular solution. Suppose we have a directory with many sub-directories, all of them with its own makefile:

root-dir\
    +----subdir1
    +----subdir2
    ...
    +----subdirn

then, just copy in the root-dir this Makefile:

SUBDIRS = $(shell ls -d */)
all:
    for dir in $(SUBDIRS) ; do \
        make -C  $$dir ; \
    done