Fixes: #40389
Update toolchain handling to use zephyr_get() to ensure consistent
handling of CMake cache variables, environment variable, and CMake
local variables.
Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
The icx compiler of oneApi will invoke clang-cl on windows,
this is not supported in zephyr now, so change to use
clang directly.
And the clang from oneApi can't recognize those cross
compiling target variables of cmake, such as
CMAKE_C_COMPILER_TARGET, so used other cmake functions
to pass them to clang.
Signed-off-by: Chen Peng1 <peng1.chen@intel.com>