[libc-commits] [libc] [libc] don't over include stdlib in the hdr declaring bsearch (PR #89471)

[via libc-commits]

enh-google wrote:

interestingly, it looks like bionic and glibc disagree on the nullability? bionic has
```
void* _Nullable bsearch(const void* _Nonnull __key,
                        const void* _Nullable __base,
                        size_t __nmemb, size_t __size,
                        int (* _Nonnull __comparator)(const void* _Nonnull __lhs, const void* _Nonnull __rhs));
```
iirc we went with a non-null base, but found too much code that felt that that should be fine as long as nmemb is 0 (and our implementation was fine with that anyway).

https://github.com/llvm/llvm-project/pull/89471