This GNOME release cycle (3.18), we plan to do the last ever release of gnome-common. A lot of its macros for deprecated technologies (scrollkeeper?!) have been removed, and the remainder of its macros have found better replacements in autoconf-archive, where they can be used by everyone, not just GNOME.
We plan to make one last release, and people are welcome to depend on it for as long as they like. However, if you want new hotness, port to the autoconf-archive versions of the macros; but please do it in your own time. There will be no flag day port away from gnome-common.
Note that, for example, porting to AX_COMPILER_FLAGS is valuable, but will probably require fixing a number of new compiler warnings in your code due to increased warning flags. We hope this will make your code better in the long run.
There’s a migration guide here: https://wiki.gnome.org/Projects/GnomeCommon/Migration.
We’ve tried to make the transition as easy and smooth as possible, but there will inevitably be hiccups. Please let me know about anything which breaks or doesn’t make sense, or discuss it on the desktop development list thread. First person to complain about -Wswitch-enum gets a prize.
When building from a tarball of a module which uses the new macros, you will no longer need gnome-common installed. (Although you may not have needed it before.)
In the 3.14.0 release, gnome-common installed some early versions of the autoconf-archive macros which conflicted with what autoconf-archive itself installs. It now has a --[with|without]-autoconf-archive configure option to control this. We suggest that all packagers pass --with-autoconf-archive if (and only if) autoconf-archive is packaged on the distribution. See bug #747920.
m4-common must not be packaged. See its README. m4-common is essentially a caching subset of autoconf-archive.
For continuous integrators
Modules which use the new AX_COMPILER_FLAGS macro gain a new standard --disable-Werror configure flag, which should be used in CI systems (and any other system where spurious compiler warnings should not cause total failure of a build) to disable -Werror. The idea here is that -Werror is enabled by default when building from git, and disabled by default when building from release tarballs and in buildbots.
For further discussion