Hi! I've tried to run Cycles render using Mesa OpenCL implementation and got an easily fixable kernel compilation error. It's still present in your git master, please fix it :) the patch is attached:
System Information
Linux 3.16.2, Radeon 8770M, Mesa 10.4-dev from OIBAF ppa, LLVM 3.5
Blender Version
Broken: 2.71, also in git master (checked on git.blender.org)