configure: update enable-llvm-shared-libs comments

 - As of commit cb080a10b68(configure.ac: Don't require shared LLVM when
building OpenCL) opencl does not mandate using shared llvm.
 - Add a warning message that building with static llvm may cause
compilation problems.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Jon TURNEY <jon.turney@dronecode.org.uk>
Reviewed-by: Tom Stellard <thomas.stellard@amd.com>
1 file changed