Verilator

Modern MinGW C runtime versions (starting from GCC 6) have switched to C99/C++11 compliant printf/scanf format specifiers when <cstdio> include is used.

OTOH, when <stdio.h> include is used, MinGW still defaults to MS formats, but even then it can be overridden with

#define __USE_MINGW_ANSI_STDIO 1

Source: https://sourceforge.net/p/mingw-w64/wiki2/printf%20and%20scanf%20family/

For GCC 5 MinGW and older, <cstdio> behaved just like <stdio.h>.

verilatedos.h header still assumes that MinGW always uses MS formats, which breaks printing of 64-bit numbers on 32-bit MinGW GCC 6, 7 and 8. Compiling verilated.cpp also prints an array of printf format warnings with modern MinGW compilers for the 32-bit Windows target.

I've attached a patch which makes both old and new MinGW compilers use the standard printf formats. Older MinGW versions are just forced to use C99 formats with the above preprocessor definition.