Allow to build on Solaris

[psumbera]

[asutherland]

For extra context, this PR is being proposed to help make sqlite-vec build in Firefox on Solaris as part of https://bugzilla.mozilla.org/show_bug.cgi?id=1962061. I am reviewing the changes in Firefox and was wondering why the typedefs were there. As I've commented at https://github.com/asg017/sqlite-vec/commit/bf0886b3b7b9a88ce5d275de6420c77c0b392ad3#commitcomment-156156175 on the fresh discussion there, I think a better fix might be just to remove the u_int16_t/similar typedefs since there is now an #include <inttypes.h> that wasn't there when they were added.