For RISC-V and Cortex-M-not-3, triples are known and have worked in some
configuration, but do not work at the moment and stay disabled until the
reference platforms (native, M3) have been established well.
This introduces KCONFIG_BOARD_CONFIG and KCONFIG_CPU_CONFIG variable for
boards and CPUs (including common directories) to add default
configuration files to be merged. The current approach, as it uses
Makefile.features, would include boards first, not allowing them to
override CPU configurations.
- Add libstdcpp feature to indicate a platform is providing a libstdc++
implementation ready for use
- The existing cpp feature now only indicates a working C++ toolchain without
libstdc++. (E.g. still useful for the Arduino compatibility layer.)
- Added libstdcpp as required feature were needed
- Added some documentation on C++ on RIOT
This adds cortexm_fpu to the DEFAULT_MODULE list when the feature
cortexm_fpu is provided by the architecture. It also moves the
dependency resolution of this module to the architecture-specific
Makefile.dep file.
