Consider using NDEBUG instead of DEBUG, _DEBUG

[kuzminrobin]

The standard of C and C++ assumes by default that the code is compiled in debug mode (which affects such things as, e.g. assert() macro). If the developer wants to compile the code in non-debug mode, then the C/C++ standards prescribe to define the NDEBUG macro (search for NDEBUG here).

Consider removing the DEBUG, _DEBUG and similar macros/definitions from our code and using the NDEBUG instead.

Some more info is here.