The idea was to cut all text after the last _ from the core's path. The goal being to make 'nestopia_libretro.info' match nestopia_libretro_ios.dylib, nestopia_libretro_qnx.so and so on.

On iOS this broke things because fill_pathname doesn't handle paths where the file has no extension but one of the directories in the path does.

    fill_pathname(buf, "/Applications/RetroArch.app/modules/nestopia_libretro", ".info", sizeof(buf));
    printf("%s\n", buf); // Outputs "/Applications/RetroArch.info"