Distributing sources partially

[Guillaume Rousse]

A colleague of mine has some concerns with source distributions.

He is using a private lexical resource to produce C source code, and he
use this source code in its own program. Unfortunatly, he doesn't have
the right to distribute the lexical resources, but assumes he can
distribute the generated C source code, as retro-conversion is impossible.

First, it is possible to distribute such software under GPL, or any
other free or open-source software, if some of those sources are
actually machine-generated and can't be regenerated by the end user ?

Second, how to achieve this using automake ? We attempted something as:

data/Makefile.am:
noinst_DATA = foo.c
foo.c: foo.txt
    ...
foo.txt: bar.txt
    ...
bar.txt: baz.txt
    ...

src/Makefile.am
bin_PROGRAMS = foo
foo_SOURCES = ../data/foo.c

In generated archive, foo.c was correctly included, but not its
dependencies (foot.txt and bar.txt). Unfortunatly, 'make' begin by
attempting to recreating them, and fails :(