Allow naming threading resources from PASE for debugging purposes

Being able to name pthread threads, mutexes, locks, and other multi-threading resources was added to the ILE in IBM i 7.1. Thread naming is a popular non-POSIX extension to pthread, but other pthread objects being nameable is an IBM i-specific change. However, this functionality wasn't added to PASE, and AIX has no functional equivalent. This means applications using PASE cannot name threads without a somewhat hairy manual call to the ILE, including converting strings and only working on the current thread due to an inability to convert PASE to ILE pthread handles.

What could be added is a version of pthread_setname_np (and others) that work with PASE pthread handles. In case AIX decides to add this functionality in the future, they can be prefixed with Qp2 for PASE specific functionality, like Qp2getifaddrs. Alternatively or in addition to this, a generic way to convert PASE to ILE pthread handles could be useful.

Being able to name threads would simplify debugging threaded applications; particularly heavily multi-threaded PASE applications where there are several similar threads running concurrently (say, in a thread pool, where all workers have the same thread function), but must be distinguished. A user could go into "Work with Jobs", select the job, show its threads, and all threads with their names would be shown.

Being able to name other resources could be useful, but may require more invasive changes to program portability; whereas thread naming is usually accounted for by programs and require minimal changes for PASE.