[CMake] resetting CHECK_INCLUDE_FILE

[Peter Soetens]

A usecase I have:

The user runs 'cmake', a header is not found. The user installs the missing 
library. The user runs cmake again. The CHECK_INCLUDE_FILE does no longer 
check if the file is present. It is again not found !

Is there a way to 'reset' the checking behaviour of CHECK_INCLUDE_FILE such 
that it is done every time ??

Thanks,
Peter
-- 
Peter Soetens -- FMTC -- <http://www.fmtc.be>