Error in building POCL

I am facing errors while trying to compile POCL. I did the following steps
1) Downloaded the code through bzr branch lp:pocl command.
2) Installed autoconf, automake, libtool through mac port.
3) Installed LLVM 3.0 and CLANG 3.0 after downloading from http://llvm.org/releases/download.html.
4) Now to build POCL,executed the following commands in sequence [./autogen.sh] [./configure --enable-debug] [sudo make]

Compilation is stopped as more than 20 errors pop up:
Error in include/_kernel.h: 231:1: error: use of undeclared identifier 'half'
Error in include/_kernel.h: 876:1 error: unknown type name '__global ' _CL_DECLARE_FUNC_V_VPV(fract)

My machine is a MAC machine having 10.6.8. Please help me.