The macros CONCAT(), MIN(), and MAX() are defined over and over again in
RIOT's code base. This de-duplicates the code by moving the macros to a
common place.
Currently implementations of the MTD api are selecting the module,
this makes it easy for default backends to be selected. But the
correct modeling is simply selecting the MTD api and then selecting
a backend. BOARDs providing one of the backends can expose this and
then that backend can be selected by default.
There is also currently nothing preventing from using the MTD api
with no backend since a mock backend can easily be provided as is
done in all mtd tests.
Some modules used a 'NATIVEINCLUDES' with different include path and no other
included directories.
It was defining basic 'include' in a different order and not using other things
defined in INCLUDES.
After doing some checks with the given include path and possible conflicting
files, there should be no conflict when using the default one.
* No common headers between all the NATIVEINCLUDES directories
* No common headers files between board/native/include, cpu/native/include and
other files in the repository (except other boards/cpus of course).
