Semicolon-separated list of directories
to be ignored by the various find...() commands.
For find_program(), find_library(), find_file(),
and find_path(), any file found in one of the listed directories
will be ignored. The listed directories do not apply recursively, so any
subdirectories to be ignored must also be explicitly listed.
|CMAKE_IGNORE_VAR| does not affect the search prefixes used by these
four commands. To ignore individual paths under a search prefix
(e.g. bin, include, lib, etc.), each path must be listed in
|CMAKE_IGNORE_VAR| as a full absolute path. |CMAKE_IGNORE_PREFIX_VAR|
provides a more appropriate way to ignore a whole search prefix.
find_package() is also affected by |CMAKE_IGNORE_VAR|, but only
for Config mode searches. Any <Name>Config.cmake or
<name>-config.cmake file found in one of the specified directories
will be ignored. In addition, any search prefix found in |CMAKE_IGNORE_VAR|
will be skipped for backward compatibility reasons, but new code should
prefer to use |CMAKE_IGNORE_PREFIX_VAR| to ignore prefixes instead.