It works! It seems that I have an include folder in Dev-Cpp and an include folder in Dev-CPP/Mingw32.

It looks like Dev-c++ was using the Dev-CPP/Include one.

However I've noticed that the allegro version comes out as 4.1.14 rather than 4.1.16.

It likes like I have old junk left there.. Waah!

Haha. Just the typical devcpp-is-to-blame I wonder if the Allegro distributions could somehow be made more clever so they detect this. Maybe check in allegro_init if the DLL version and the header version is the same?

Maybe:

#define allegro_init() allegro_init_version_check(ALLEGRO_VERSION_STR)

allegro_init_version_check(char const *str)
{
    if (strcmp (str, ALLEGRO_VERSION_STR))
        allegro_message ("Wanring! Your headers version is different from the library version!");
}

Of course, this would need more than a simple strcmp, e.g. 4.0.0/4.0.3 would be ok.. but it would have detected this particular case at least.