This avoids a cryptic DTC failure when compiling trying to compile
native_posix with a missing gcc or clang.
REQUIRED is available since CMake 3.18
Example with clang, cryptic error without this commit:
```
ZEPHYR_TOOLCHAIN_VARIANT=llvm west build \
-p -b native_posix samples/hello_world/
-- Found toolchain: host (clang/ld) <= this is wrong
-- Found Dtc: /usr/bin/dtc (found suitable version "1.6.1", minimum ...
-- Found BOARD.dts: zephyr/boards/posix/native_posix/native_posix.dts
CMake Error at /zephyr/cmake/modules/dts.cmake:191 (message):
command failed with return code: No such file or directory
Call Stack (most recent call first):
zephyr/cmake/modules/zephyr_default.cmake:113 (include)
zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:66 (include)
zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:92 (include_boil...
CMakeLists.txt:5 (find_package)
```
Well hidden behind the scenes, dts.cmake fails above because it invokes
`CMAKE_C_COMPILER-NOTFOUND`
With this commit:
```
ZEPHYR_TOOLCHAIN_VARIANT=llvm west build \
-p -b native_posix samples/hello_world/
-- Found toolchain: host (clang/ld) <= this is still wrong
CMake Error at zephyr/cmake/compiler/clang/generic.cmake:7 (find_program):
Could not find CMAKE_C_COMPILER using the following names: clang
```
Signed-off-by: Marc Herbert <marc.herbert@intel.com>
For each compiler, also set a CMAKE_GCOV var referencing the appropriate
gcov tool.
Tested with gcc and host-gcc on the ChromeOS codebase.
Signed-off-by: Jeremy Bettis <jbettis@chromium.org>
Update the files which contain no license information with the
'Apache-2.0' SPDX license identifier. Many source files in the tree are
missing licensing information, which makes it harder for compliance
tools to determine the correct license.
By default all files without license information are under the default
license of Zephyr, which is Apache version 2.
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
Split up the toolchain configuration into two phases, generic and
target. The 'generic' phase configures the toolchain just enough to be
able to preprocess DT files. The 'target' phase completes the
configuration with target-specific configuration.
Signed-off-by: Sebastian Bøe <sebastian.boe@nordicsemi.no>
