It is quite often the project description has used in a real world software.
Examples include:
* part of a help screen of the application
* builtin resources (`*.rc` files, data for "About" dialog of a GUI app, & etc)
* most generators for CPack can use it
* it could be used by documentary software (Doxygen, Sphinx) which is usually
integrated to CMake based projects via `add_custom_target()`
Now `project()` call learned an optional `DESCRIPTION` parameter with a
short string describing a project. Being specified, it would set the
`PROJECT_DESCRIPTION` variable which could be used in `configure_file()`
or whatever user wants. Also `PROJECT_DESCRIPTION` is a default value
for `CPACK_PACKAGE_DESCRIPTION_SUMMARY`.
The check added in commit v3.6.0-rc1~293^2 (Diagnose recursive
project/enable_language without crashing, 2016-03-07) broke support for
enabling `RC` explicitly along with other languages like `C`. The
reason is that we enable all listed languages at once so the internal
`enable_language(RC)` that we do while enabling `C` or `CXX` on some
platforms triggers the recursion check if `RC` is explicitly listed.
Ideally we should refactor things to only enable one language at a time,
but for now it is simplest to just exclude `RC` from the explicit list
until other languages are enabled, and then enable it.
Closes: #16330
Teach the project() command to set variables
{PROJECT,<PROJECT-NAME>}_VERSION{,_MAJOR,_MINOR,_PATCH,_TWEAK}
holding the project version number and its components. Add project()
command option "VERSION" to specify the version explicitly, and default
to the empty string when it is not given.
Since this clears variables when no VERSION is given, this may change
behavior for existing projects that set the version variables themselves
prior to calling project(). Add policy CMP0048 for compatibility.
Suggested-by: Alex Neundorf <neundorf@kde.org>
Teach the project() command to recognize an optional "LANGUAGES"
keyword after the project name and prior to the list of languages.
Do not allow multiple copies of the keyword. If the keyword is
specified and no languages are listed, imply NONE.
