;-list of directories to be ignored by
find_path() commands. This is useful in cross-compiling
environments where some system directories contain incompatible but
possibly linkable libraries. For example, on cross-compiled cluster
environments, this allows a user to ignore directories containing
libraries meant for the front-end machine.
By default this is empty; it is intended to be set by the project.
CMAKE_IGNORE_PATH takes a list of directory names, not
a list of prefixes. To ignore paths under prefixes (
lib, etc.), specify them explicitly.