If the value argument to set_ifndef() may be unset, the entire value
must be double-quoted to avoid a CMake syntax error.
Fix call sites which don't handle this, or which otherwise make
non-idiomatic use of this function.
Signed-off-by: Marti Bolivar <marti@opensourcefoundries.com>
Move toolchain definitions into toolchain/ and move compilers to
compilers/
Usage of toolchain- for everything was confusing, there are the actual
compiler related definitions and there is the toolchain/SDK related
configs, so keeping them separate helps understand the different and
prevents confusion.
Signed-off-by: Anas Nashif <anas.nashif@intel.com>