The big Blender Sculpt Mode thread (Part 1)

I keep running into this one.

runningllvm-config-
– Could NOT find LLVM (missing: LLVM_LIBRARY)
– LLVM not found
CMake Error at CMakeLists.txt:909 (message):
Cycles OSL requires WITH_LLVM, the library may not have been found.
Configure LLVM or disable WITH_CYCLES_OSL

I can build blender 2.8 perfectly fine, but when i try building the sculpt branch, it fails with this message…