Add a variable to indicate the latest standard known to be supported for
each language:
* `CMAKE_C_STANDARD_LATEST`
* `CMAKE_CXX_STANDARD_LATEST`
* `CMAKE_CUDA_STANDARD_LATEST`
* `CMAKE_HIP_STANDARD_LATEST`
* `CMAKE_OBJC_STANDARD_LATEST`
* `CMAKE_OBJCXX_STANDARD_LATEST`
These variables, more generally referred to as
`CMAKE_<LANG>_STANDARD_LATEST`, are assigned an integer value which
represents the minimum between the latest version of the associated
language standard supported by the current compiler and the latest
version supported by CMake.
Add documentation for these variables in a new page called
`CMAKE_<LANG>_STANDARD_LATEST` was added under the "Variables for
Languages" section of the `cmake-variables(7)` page.
Update each compiler-specific CMake script under
`${CMAKE_ROOT}\Modules\Compiler` to manually define the relevant
`CMAKE_<LANG>_STANDARD_LATEST` variable as necessary. This will
require updating and maintaining as newer compiler versions become
recognized by CMake.
Closes: #25717
Unset irrelevant compile option variables in the following scripts:
* `${CMAKE_ROOT}\Modules\Compiler\ARMClang-C.cmake`
* `${CMAKE_ROOT}\Modules\Compiler\TIClang-C.cmake`
* `${CMAKE_ROOT}\Modules\Compiler\TIClang-CXX.cmake`
These scripts all include either
`${CMAKE_ROOT}\Modules\Compiler\Clang-C.cmake` or
`${CMAKE_ROOT}\Modules\Compiler\Clang-CXX.cmake`, and those scripts
will set various compile option variables based on what the
standard version of Clang supports. However, these do not
necessarily apply to ARMClang and TIClang. This commit thus
explicitly unsets all of the compile option variables which are not
manually defined for these compilers.
Add TIClang compiler ID and support in compiler modules. Update
documentation. Add rudimentary RunCMake test for TIClang to test
basic functionality.
Fixes: #24619
