Fixes: #36558#32577
This commit introduces CMAKE_C_COMPILE_FEATURES and
CMAKE_CXX_COMPILE_FEATURES.
This allows users to use the `target_compile_features()` in their own
code.
In Zephyr, the CMAKE_C/CXX_COMPILE_FEATURES are defined based on the
compiler and the Kconfig / CSTD setting.
Doing so ensures that a user compiling Zephyr with c99 and specifies
`target_compile_features(<target> ... c_std_11)` will get an error.
And similar if building Zephyr with C++ support and c++11, but testing
for `target_compile_features(<target> ... cxx_std_17)`.
For example in the C++ case, the user must ensure that Zephyr is
compiled with C++17, that is: CPLUSPLUS=y and STD_CPP17=y, in which case
the CMAKE_CXX_COMPILE_FEATURES will contain support for C++17 and thus
the `target_compile_features(<target> ... cxx_std_17)` will succeed.
Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
917d5021d7