This function is a builder for .objects files and creates a file containing
all the object-file dependencies of the current directory. Any .objects files
specified as a dependency to the .objects file being built will be expanded;
that is, a .objects file contains all of the object file dependencies of the
current directory and all subdirectories it depends on.
These files are used to quickly find all the dependencies of a (sub)directory
for inclusion in e.g. linking.
AddRule 'my.objects', [
'%TARGET_PATH/my.objects' => 'subdir/other.objects'
=> \&CreateObjectsFile ;