pctrie: avoid typecast

[dougm]

Summary

Have PCTRIE_RECLAIM_CALLBACK typecast one function pointer type to another, to relieve the writer of the call back function from having to cast its first argument from void* to member type.

[dougm]

Get rid of a callback function pointer type that would only create a namespace collision someday when somebody used two pctries in the same compilation unit.

[rlibby]

LGTM. Did you check that clang and gcc don't produce warnings? I don't think they should. I can try applying and checking this evening if you haven't already.

[dougm]

In D45586#1040101, @rlibby wrote:

LGTM. Did you check that clang and gcc don't produce warnings? I don't think they should. I can try applying and checking this evening if you haven't already.

I did not. Please check it out.

[rlibby]

I checked for warnings, nothing new in subr_pctrie.c, subr_rangeset.c, or swap_pager.c. Good to go.

gcc13 is producing a few warnings for subr_pctrie.c, but I don't think any are actual problems. meta file here:
https://people.freebsd.org/~rlibby/gcc13-subr_pctrie.o.meta

• The -Wcast-qual stuff is due to atomic_load_ptr, nothing to be done about that here for pctrie.
• The -Wmaybe-uninitialized I'm pretty sure is a false positive. It could be silenced with a NULL initialization though.
• The -Wattributes I think are harmless... Not sure if there's a nice way to silence those.