Safer NK_LEN macro

[ryuukk]

Protects from division by 0 and when used from <= C11

https://stackoverflow.com/a/1598827

[aganm]

C++ sizeof will never return 0.

From C++ standard, 9/3 "Classes": "Complete objects and member subobjects of class type shall have nonzero size."

[dumblob]

IMHO if the new macro helps in some real cases or for some compilers, then we can merge this. Any such examples @ryuukk ?

[N-R-K]

C++ sizeof will never return 0.

Neither will C. The lowest addressable unit is defined to be char which will always be 1 byte. And you cannot apply sizeof to a bit-field.

[ryuukk]

Sorry i didn't meant "and when used from C++"

I meant when used with a <= C11 compiler, it'll refuse to compile

[riri]

Looks ok to me too

Just missing nuklear.h build and version bump