[MayCXC]

Compiled with -DSQLITE_CORE, as when sqlite-vec.c is built into SQLite or into an application, sqlite3_vec_init(), sqlite3_vec_numpy_init() and sqlite3_vec_static_blobs_init() never read their pApi parameter: SQLITE_EXTENSION_INIT2() is its only use, and SQLITE_CORE leaves it out. A project that compiles the file into its own binary with -Wall -Wextra gets three warnings from main, with gcc 14.2 and with clang 19.1:

$ ./scripts/vendor.sh
$ gcc -Ivendor -Wall -Wextra -DSQLITE_CORE -DSQLITE_VEC_STATIC -c sqlite-vec.c -o vec.o
sqlite-vec.c:12525:65: warning: unused parameter 'pApi' [-Wunused-parameter]
sqlite-vec.c:12610:71: warning: unused parameter 'pApi' [-Wunused-parameter]
sqlite-vec.c:12629:59: warning: unused parameter 'pApi' [-Wunused-parameter]

(gcc's source excerpts under each warning are trimmed.) The Makefile's static target compiles without -Wall -Wextra, so the project's own builds do not print them.

Each function now marks pApi with UNUSED_PARAMETER() in the SQLITE_CORE case, as sqlite3_vec_numpy_init() and sqlite3_vec_static_blobs_init() already do for pzErrMsg. The commit adds a ### Fixed entry under [Unreleased] in CHANGELOG.md, at the head of the list, where it merges cleanly with main at a791836 and with #4, #7, #8, #11 and #12.

Test. The command above prints the three warnings on main and none on this branch, with either compiler. UNUSED_PARAMETER() is a (void) cast, so the object files are byte-identical before and after, both for the loadable extension and with -DSQLITE_CORE. make test-loadable (449 passed, 3 skipped) and make test-unit pass.

The same change is open on vlasky/sqlite-vec as vlasky#23, and on asg017/sqlite-vec as asg017#341, where only sqlite3_vec_init() remains of the three.

[mceachen]

Landed as 20cea6b, thanks. Follow-up 0fbb507 limits the CHANGELOG entry to the pApi warning: gcc -O3 still reports eight -Wmaybe-uninitialized warnings in -DSQLITE_CORE builds.