make_dir() to support creation modes other than 0755
freeciv-web currently patches make_dir() to create all directories with mode 0775. Let's make mode parameter to the function, so that freeciv-web can limit that elevated mode only to the case where it's needed.
freeciv-web currently patches make_dir() to create all directories with mode 0775. Let's make mode parameter to the function, so that freeciv-web can limit that elevated mode only to the case where it's needed.