obtain version from git describe

[garlick]

The old style CHAOS META file is still in use in this project. Drop it and get the version from git describe --always.

[pete4abw]

See Git Describe Program. It works when git clone/pull is used. However, depending how it's used in configure.ac downloaded files will not have .git directory and may not work.

Sample configure.ac which I use:

m4_define([v_maj], [m4_esyscmd_s([./util/gitdesc.sh major])])  
m4_define([v_min], [m4_esyscmd_s([./util/gitdesc.sh minor])])  
m4_define([v_mic], [m4_esyscmd_s([./util/gitdesc.sh micro])])  
m4_define([v_ver], [v_maj.v_min.v_mic])  

Note: This will fail if tarballs are downloaded from git repo.

[garlick]

This is what I had in mind and have standardized on in other projects:

AC_INIT([flux-core],
        m4_esyscmd([git describe --always | awk '/.*/ {sub(/^v/, ""); printf "%s",$1; exit}']))