[CMake] CheckIncludeFiles: how to use?

[Marcel Loose]

Hi all,

Maybe it's because of a partially sleepless night, but I can't seem to
figure out how I should use check_include_files().

According to the docs (and the implementation) this macro should be used
as:

  CHECK_INCLUDE_FILES(INCLUDE VARIABLE)

where INCLUDE should contain the list of files to include.
Problem is, however, that the following doesn't work:

  CHECK_INCLUDE_FILES(unistd.h stdio.h var)

because this will assign "unistd.h" to the variable INCLUDE and
"stdio.h" to the variable VARIABLE.

The following also doesn't work:

  SET(files unistd.h stdio.h)
  CHECK_INCLUDE_FILES(files var)

because the variable INCLUDE is not handled as the name of the list
containing the header files, but as the name of the header file itself.

Am I missing something here, or is this a bug in check_include_files()?

Best regards,
Marcel Loose.