Compiling under GCC (Ubuntu on 20.04)

[axel-capodaglio]

I am trying to compile CStdString.h under GCC 9.3.0, but I get many warnings "warning: statement has no effect [-Wunused-value]" Changing #define UNUSED(x) x to #define UNUSED(x) (void)x removes many of them; however UNUSED() should be applied also to the various szCvt; empty instructions in ssadd and ssasn.