arc4random_buf on OpenBSD for random bytes instead of opening /dev/arandom

[iwanluijks]

In the php_session_create_id function a file descriptor is opened to the configured session.entropy_file by default, on non-Windows OSs and OSs that don't have an entropy_file available at compile time.
This is effectively described in the comments above session.entropy_file:

; On systems that don't have /dev/urandom but do have /dev/arandom, this will default to /dev/arandom
; If neither are found at compile time, the default is no entropy file.
; On windows, setting the entropy_length setting will activate the
; Windows random source (using the CryptoAPI)

In OpenBSD however, there is no need for this, as the arc4random functions are available as a fast random source, generating high quality pseudo-random number streams.
This eliminates the usage of a file descriptor on these systems.

The idea herein is to extend the comments with an extra line:

; On OpenBSD, setting the entropy_length setting will use arc4random instead

[weltling]

Could you please rewrite this patch using php_random_bytes() which is available since 7.0 and already takes care about these platform details?

Thanks.

[iwanluijks]

Great suggestion, that also cleans up the ugly mess of code in the php_create_session_id. I'll get back with a pull request when it is ready.

[jpauli]

Thank you for resubmitting a PR according to what has been said.
Closing now