Package: mesa
Version: 18.2.1
Building the package for stretch leads to a build failure due to an upstream bug Re: libxcb version issues.
Bug is fixed in upstream as commit:
dd333c66bdcb11c0d7c5 "vulkan: Disable randr lease for libxcb < 1.13"
If mesa 18.2.1 gets built for stretch-backports, you'll need to pull this commit in as a patch so it'll build. This commit hopefully should make it into 18.2.2.
Hope this helps.
--
Stuart Young (aka Cefiar)