- Added intro code block showing how to include this module.
- Added a list of variables that can affect the check. The
CMAKE_REQUIRED_LINK_OPTIONS is skipped as it is currently internally
overridden by the module's check command.
- Added examples section.
- Described command arguments as a list.
- Added included section describing the `LINKER:` (and `SHELL:`) prefix.
- Added link to the module in target_link_options() docs.
The module was added in CMake 3.18 by commit af96c0f4fa
(CheckLinkerFlag: Add module to check validity of linker flags,
2020-05-16, v3.18.0-rc1~103^2), but it is still possible for projects to
use it without setting policies to the 3.18 version level.