[Cmake] Removing a cache entry? Multiple MACRO definitions?

[Amitha Perera]

Hi all

1)

How can I remove a cache entry in CMake? I want to force a re-test of
a CHECK_INCLUDE_FILE without generating a new variable name. Something
like this:

CHECK_INCLUDE_FILE( stdlib.h HAVE_STDLIB )
# removes definition from memory, but not cache file
SET( HAVE_STDLIB )
# Will not re-run check because entry exists (in cache file)
# How can I force it?
CHECK_INCLUDE_FILE( stdlib.h HAVE_STDLIB )


2)

Is it permissible to define the same macro twice? I.e. is

INCLUDE( ${CMAKE_ROOT}/Modules/CheckIncludeFile.cmake )
INCLUDE( ${CMAKE_ROOT}/Modules/CheckIncludeFile.cmake )

valid?

Thanks,
Amitha.