In order to understand how to use the more advanced
features, you must first understand how
make dist is
implemented. For most packages, what we've already covered will
suffice. Few packages will need the more advanced features, though I
note that many use them anyway.
dist rules work by building a copy of the source tree and
then archiving that copy. This copy is made in stages: a
`Makefile' in a particular directory updates the corresponding
directory in the shadow tree. In some cases,
automake is run
to create a new `Makefile.in' in the new distribution tree.
After each directory's `Makefile' has had a chance to update the
distribution directory, the appropriate command is run to create the
archive. Finally, the temporary directory is removed.
If your `Makefile.am' defines a
dist-hook rule, then
Automake will arrange to run this rule when the copying work for this
directory is finished.
This rule can do literally anything to the distribution directory, so
some care is required -- careless use will result in an unusable
distribution. For instance, Automake will create the shadow tree using
links, if possible. This means that it is inadvisable to modify the
files in the `dist' tree in a dist hook.
One common use for this rule is to remove files that erroneously end up
in the distribution (in rare situations this can happen). The variable
`distdir' is defined during the
dist process and refers to
the corresponding directory in the distribution tree; `top_distdir'
refers to the root of the distribution tree.
Here is an example of removing a file from a distribution: