Updated Portuguese translation
Updated Russian translation
Updated Danish translation
Updated Serbian translation
Updated slovak translation
[l10n] Update Catalan translation
Updated slovak translation
Updated slovak translation
Updated Indonesian translation
User docs: Fix broken link
User docs: Fix 404 link
User docs: Update URL
User docs: Remove non-existing See Also page
Prepare 3.12.0
Do not unconditionally call prctl in distributed C

The existing check for linux/prctl.h works great if you are compiling
the Vala code, but it's expected that users and distributions may start
with the distributed C files instead. If the tarball is generated on
Linux, then the call to prctl() will unconditionally appear in the
distributed C, and if the tarball isn't generated on Linux, then it will
be unconditionally absent.

There are only two ways to fix this: (a) not distribute any C code, or
(b) move the conditional compilation out of the Vala code. Though it
looks like the Autotools Vala world may be starting to lean towards (a),
let's be conservative and pick (b) for now.

https://bugzilla.gnome.org/show_bug.cgi?id=726614
Update header bar title after Undo

Now that we display the name of the player to move, we need to remember
to keep this updated even if we go back in time.

https://bugzilla.gnome.org/show_bug.cgi?id=726950
ui: remove unnecessary size groups

The horizontal size group is exacerbating the horrible resizing
behavior as the clock ticks down. It's not the size group's fault that
this is broken, but the size group makes it 1634435x worse.

The vertical size group is simply unnecessary in 3.12. In 3.10 it is
needed for the header bar buttons to have the same height, but forces
the buttons into odd (non-square) shapes. Let's just remove it.

https://bugzilla.gnome.org/show_bug.cgi?id=726951
Use the correct ratio character for the time label

https://bugzilla.gnome.org/show_bug.cgi?id=726954
Compute the width of the time labels at runtime

Set the time labels to be a little bit wider than the widest they might
ever be, so they never resize.

This assumes that each player will be limited to at most 999 minutes,
which currently is not the case, but will be soon.

https://bugzilla.gnome.org/show_bug.cgi?id=726955
Updated Basque language