For 53 bits double, to make same math result across platform,
maybe add this to Lua.c ? (even if not needed)
fesetenv (FE_PC53_ENV);
I suspect the result of that will not be truly cross-platform. Most platforms will fail to compile that [1], but I guess there is one that you happen to use (which one is it?) where that works. To make this truly cross-platform, you should rather say in its stead: #error I cannot set floating-point precision in a cross-platform way [2]
