bsearch(3): support arrays with more than INT_MAX elements

bsearch(3): support arrays with more than INT_MAX elements

The "lim" variable needs to be a size_t to match nmemb, otherwise we
get undefined behavior when nmemb exceeds INT_MAX.

Prompted by a blog post by Joshua Bloch:

https://ai.googleblog.com/2006/06/extra-extra-read-all-about-it-nearly.html

Fixed by Chris Torek a long time ago:

https://svnweb.freebsd.org/csrg/lib/libc/stdlib/bsearch.c?revision=51742&view=markup

ok millert@