Fix incrementing version number in autoconf/automake projects

[alkuna]

On development projects using GNU autoconf and automake tools, the version number should be updated in configure.ac and configure files when hot-fixing or releasing with omgf.

This patch checks for existence of configure.ac file and invokes autoreconf -f command to regenerate the configure script before adding and committing changes.

Development projects using autoconf and automake should be changed to fully advance this patch in the following sence:

1. A configure.ac file has to read the version number from VERSION file using proper m4 macro, e.g.:

AC_INIT(project,` m4_esyscmd_s([cat VERSION]), Author <[email protected]>)

2. autom4te.cache directory generated by autoreconf is not intended for commit, thus it should be added to .gitignore.

[jnv]

Thank you Alexander! I think this would be a perfect use case for the planned hooks support, see #52. What do you think, @petrzpav?

[alkuna]

Hook was exactly my first idea. It is more universal. There are other build systems like autogen.sh, cmake, etc.
I vote for hooks, it allows to specify more parameters to autoreconf according to actual project or developer needs.

[alkuna]

Another hook examples related to debian packaging would be:

1. updating debian/changelog file with calling, e.g. dch -v $(cat VERSION) "New upstream release" during version incrementing,
2. finalizing debian/changelog with dch -r before merging to dev and master.

[petrzpav]

@jnv Yes it is very nice use-case for hooks.
@alkuna Thanks for your support and examples! Hooks will be available in the next minor version

[alkuna]

The pull request is no longer relevant in favor of Hooks support.