RfC: New C rewrite of SLSQP in SciPy

[ilayn]

Greetings,

Though not exactly an issue but hopefully relevant for folks here too. As a part of our F77 code rewrite effort https://github.com/scipy/scipy/issues/18566, I've rewritten SLSQP in C from scratch https://github.com/scipy/scipy/pull/22524.

Since this community is more specialized in this domain about the inner workings as opposed to our general maintenance approach to it, I just wanted to draw your attention to it in case you are interested, or have recommendations for features I forgot to add/remove, or simply mistakes I made (not really a C expert by any measure).

All feedback welcome,