Add include for NULL definition

[swaldhoer]

Add include <stddef.h> as NULL currently is only included by accident through some other headers.

[mvandervoord]

I fixed this issue by replacing the NULL with a cross-platform standard 0. Thanks for pointing out the issue! I just pivoted to a more universal solution (sadly giving up some clarity in the test, but the test name still describes it!)

[swaldhoer]

Out of curiosity, why was simply including stddef.h not the chosen solution? stddef.h is required by the standard since C89/C90 to define NULL.

[mvandervoord]

Hi @swaldhoer, because there are still embedded libraries that don't support all the standard libraries, particularly the type-related defines, etc. We've found that, to get the widest support, we aim for a dumbed-down ANSI-C-ish standard that avoids most of the standard libraries. Honestly, if we could avoid using setjmp and still be portable, we probably would. But this works for most situations, so we're going with it. It's not perfect, but it seems to be an acceptable line most of the time.

[swaldhoer]

Okay thanks for the clarificarion...however, wild to hear, that there are embedded compilers missing the most basic headers 😅