The Win32 implementation of strcasestr() defined here is currently very

heavy-handed (performs strdup/malloc's and modifications of the strings),
so a temporary hack is to perform a case-sensitive search (using the standard
strstr() function) first. The results won't exactly match the traditional
strstr() and the performance improvement is only for positive matches
(where the correct case was guessed in the passed 'needle' string arg).
TODO: re-write or copy a good/fast strcasestr() implementation for Win32 builds.