FindDocBookXML4.cmake: fix VERSION_VAR check for cmake.
cmake fixed a bug a week ago: https://gitlab.kitware.com/cmake/cmake/-/commit/12de4ea2e8efc00c57c731b4a42066ef6d20e099
After this fix, if a version number is specified in find_package
but the corresponding .cmake file does not specify VERSION_VAR in
find_package_handle_standard_args
, VERSION_OK will be set to false,
resulting in _FOUND being FALSE.
this commit fixes this error, see also: https://bugs.gentoo.org/870313
Signed-off-by: Ryan Qian i@bitbili.net
Edited by Ryan Qian