I have been thinking... maybe more consistent to add the following functions after all: _stristr, _strichr, _strrichr, _memichr (and the Unicode variations: _wcsistr, _wcsichr, _wcsrichr and _wmemichr). No compatibility names since there is not much to be compatible with...
If the functionality is present, it should easy to define a macro with the name of the function to be compatible with (strcasestr, strstri, istrstr...).
Pelle