title: how to include header correctly in the opencl kernel
body: <p>I am writing an opencl kernel with many helper function in the same .cl file. I want to package the helper function into a header file. I read the spec and see I should pass <code>-I Dir</code> in the <code>clCreateProgram</code> function call.</p>
  
  <p>I am still confused here. When I crate a A.h file to be included in the .cl file. Should I create a corresponding A.c file or A.cl file? 
  If I create a corresponding A.c file, some routines in .c file and .cl file might be different and might make the function cannot be used directly by the kernel.</p>