Move to CMake 3.20.0.
At the Toolchain WG it was decided to move to CMake 3.20.0.
The main reason for increasing CMake version is better toolchain
support.
Better toolchain support is added in the following CMake versions:
- armclang, CMake 3.15
- Intel oneAPI, CMake 3.20
- IAR, CMake 3.15 and 3.20
Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
This provides a better error message when building with CMake and
forgetting ZEPHYR_BASE or not registering Zephyr in the CMake package
registry. See parent commit for more details (split from parent for
better readability).
Signed-off-by: Marc Herbert <marc.herbert@intel.com>
Using find_package to locate Zephyr.
Old behavior was to use $ENV{ZEPHYR_BASE} for inclusion of boiler plate
code.
Whenever an automatic run of CMake happend by the build system / IDE
then it was required that ZEPHYR_BASE was defined.
Using ZEPHYR_BASE only to locate the Zephyr package allows CMake to
cache the base variable and thus allowing subsequent invocation even
if ZEPHYR_BASE is not set in the environment.
It also removes the risk of strange build results if a user switchs
between different Zephyr based project folders and forgetting to reset
ZEPHYR_BASE before running ninja / make.
Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
