Remove unneeded constant, change thread ID generation:
Remove unneeded constant, change thread ID generation:

We don't need to know the pthreads version, just that it exists. Not going to bother with version-dependent code branching.

OpenSSL may not be installed, so use md5() to generate thread IDs instead. Not doing any crypto here, it's random enough.

ampersign/php-multithreaded-resolver