In cl_gl_ext.h, there is a "/*" within a comment block. This causes compiler warnings with GCC 4.2.2, and possibly others.
Steps to reproduce:
Exact error message:
CL/cl_gl_ext.h:44:4: error: "/*" within comment
This is present in all of the presently published headers.
It looks like this was recently added though; earlier copies of cl_gl_ext.h don't have this problem.