/ X Server 1.5
is running months behind schedule, but now holding up its release is Mesa 7.1
or there the lack of. However, Adam Jackson has pushed out a new X Server 1.5 development release with a few more changes while waiting for this updated Mesa release.
This new release, xorg-server 188.8.131.526, has about two dozen bug fixes but nothing too extraordinary. The X Server 184.108.40.2066 release announcement can be read on the X.Org mailing list