Commit 7644d557df (Check*: Refactor variable handling, 2026-07-20,
v4.4.1~12^2~1) introduced a subtle regression in the handling of
`CMAKE_REQUIRED_LINK_OPTIONS` and `CMAKE_REQUIRED_LIBRARIES` which
resulted in an error if these were set to a 'false-like' value. This
could happen, for example, if the user passes `<name>_LIBS`, which
happens to have the value `<name>-NOTFOUND`. Previously, such values
would be ignored.
Fix it by separately checking for user- or module-provided link options
or link libraries. (We were already doing this for the other variables
used to propagate requirements into checks.)
Fixes: #28026