The changes in commit c96fe0b4 (cmake: Add -W options to control
deprecation warnings and errors, 2015-07-28) fail to account for
-Wdev warnings produced by places in CMake other than message().
This causes a regression in which -Wno-dev fails to suppress such
warnings. Revert the feature until it can be revised accordingly.
Improve formatting, primarily by:
* Adding links to relevant commands, properties, generators, and so on.
* Converting code, symbols, paths, and so on to fixed-width fonts.
* Hard wrapping lines to 80 characters or less.
Refactor the -Wdev and -Wno-dev to use a generic -W parser that follows
the GCC pattern. Include support for setting CMAKE_ERROR_DEPRECATED and
CMAKE_WARN_DEPRECATED via the deprecated warning. Add -Werror=dev and
-Wno-error=dev options so that dev warning options are in line with
deprecated warning options. Use a new CMAKE_SUPPRESS_DEVELOPER_ERRORS
internal cache entry to store the above new dev options persistently.
Add tests for new options and updated cmake documentation and release
notes to list new options.