from makefiles (and thus from the buildbot).
The intention is to be able to tell when a human is running the tool so we
can provide more code-review guidance.
As a starter, enable the "too many proto_tree_add_text() calls" check when
a human is running the tool.
svn path=/trunk/; revision=41943
GENERATED_H_FILES.
If we have DIRTY_GENERATED_C_FILES, use it the same way we use
GENERATED_C_FILES.
GENERATED_FILES is "everything to nuke on a "make maintainer-clean"",
not "everything to put into the distribution".
svn path=/trunk/; revision=41075