This isn't something to change in this PR, but something I noticed just from looking at this code during review. Now that we have the ability to set callbacks, could we get rid of the `C_OR_NI_OR_ARM` macros and instead set the callbacks once (either during library init, or alternatively on first use if it's not set)? Again: not something to do in this PR, but if anyone else thinks it might be good, we could create a separate issue to track.
_Originally posted by @dstebila in https://github.com/open-quantum-safe/liboqs/pull/1707#discussion_r1674441978_
See also: #1599, #1832