lang/pocl: update to 1.5
- Drop libltdl dependency after r514525 [1], see https://github.com/pocl/pocl/commit/fe65a6d44144
Changes: http://portablecl.org/pocl-1.5.html
PR: 248535
Submitted by: O. Hartmann (maintainer)
Reviewed by: kevans
Submitted by: Lars Herschke [1]