I would be interested to in knowing how you out there handle the bumping the version number for new releases issue.
How do you handle the version number in
A common solution nowadays is to invoke AC_INIT with an m4_esyscmd argument to generate the VERSION from git. For example, autoconf's configure.ac contains the lines:
AC_INIT([GNU Autoconf],
m4_esyscmd([build-aux/git-version-gen .tarball-version]),
[bug-autoconf@gnu.org])
where build-aux/git-version-gen is a simple script that calls 'git describe' to generate the version number. (see gnulib)
There are drawbacks to this approach, but it can be effective.