Log Message:
pocl: add links to upstream pull requests for patches

cpuinfo: check for fopen() failure when opening sysfs nodes to avoid segfault
https://github.com/pocl/pocl/pull/948

pocl_timing: fix detection of Unix monotonic clocks
https://github.com/pocl/pocl/pull/949

Fix detection of dlopen()/libdl
https://github.com/pocl/pocl/pull/950