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
Document these variables.
Change our convention for setting these variables from:
set(CMAKE_C_FLAGS_INIT "...")
to
string(APPEND CMAKE_C_FLAGS_INIT " ...")
so that any value previously set by a toolchain file will be used.
Automate the conversion with:
sed -i 's/set *(\(CMAKE_\(C\|CXX\|Fortran\|RC\|ASM\|${[^}]\+}\)_FLAGS\(_[^_]\+\)\?_INIT \+"\)/string(APPEND \1 /' \
Modules/Compiler/*.cmake Modules/Platform/*.cmake
and follow up with some manual fixes (e.g. to cases that already
meant to append). Also revert the automated changes to contexts
that are not protected from running multiple times.
We factor flags from Platform/Linux-PGI-Fortran.cmake into language
independent helper modules
Compiler/PGI.cmake
Platform/Linux-PGI.cmake
and invoke the macros from
Compiler/PGI-<lang>.cmake
Platform/Linux-PGI-<lang>.cmake
This enables general support for the PGI compilers.
We set the variables to contain "-v", the verbose front-end output
option for PGI compilers. This enables detection of implicit link
libraries and directories for these compilers.
Tyler