clover: Add function for building a clover::module for non-TGSI targets v6

clover: Add function for building a clover::module for non-TGSI targets v6

v2:
  -Separate IR type and LLVM triple
  -Do the OpenCL C->LLVM IR and linking steps for all PIPE_SHADER_IR
   types.

v3:
  - Coding style fixes
  - Removed compatibility code for LLVM < 3.1
  - Split build_module_llvm() into three functions:
    compile(), link(), and build_module_llvm()

v4:
  - Use struct pipe_compute_program

v5:
  - Don't malloc memory for struct pipe_llvm_program

v6:
  - Fix serialization of llvm bytecode

Reviewed-by: Francisco Jerez <currojerez@riseup.net>