meson.build: Fix mingw format specifiers
On Windows, format specifiers like "%llu" will issue a warning for 64bit integers on ancient MINGW compilers. To mitigate this problem, define __USE_MINGW_ANSI_STDIO =1 can be used to modify stdio.h behaviour
On Windows, format specifiers like "%llu" will issue a warning for 64bit integers on ancient MINGW compilers. To mitigate this problem, define __USE_MINGW_ANSI_STDIO =1 can be used to modify stdio.h behaviour