On: Checking for the absence of a string, naive AVX-512 edition

[cmrdporcupine]

There are several, but I found this one is quite useful: https://github.com/vectorclass/version2

Very minimal API, header only, so easily imported ... I then wrapped up in my own classes for my own purposes: https://github.com/rdaum/sidebands_vst/blob/main/source/dsp/...