[Beignet] Problems and questions when using Beignet

[Rebecca N. Palmer]

> When I run "./utest_run", I get 18 errors,
Those tests use the __local memory space, which does not work on Haswell 
without a kernel patch: 
https://01.org/zh/beignet/downloads/linux-kernel-patch-hsw-support

> When I run any OpenCL programs, I need root privilege
You shouldn't; you may have accidentally built beignet without X 
support.  Run

sudo apt-get install cmake pkg-config python ocl-icd-dev 
ocl-icd-opencl-dev libdrm-dev libxfixes-dev libxext-dev llvm-3.5-dev 
clang-3.5 libclang-3.5-dev libtinfo-dev libedit-dev zlib1g-dev

then recompile beignet.

> Aiming at a self-defined structure, used by host and kernel, do I need to align the bytes? If so, how many bytes should I need to align?
https://www.khronos.org/registry/cl/sdk/1.2/docs/man/xhtml/clCreateBuffer.html 
CL_MEM_USE_HOST_PTR
https://www.khronos.org/registry/cl/sdk/1.2/docs/man/xhtml/dataTypes.html