Include w32font.h.

Include w32font.h.
(struct w32font_info): Add owning_frame field.  Move to w32font.h.
(w32font_open): Set owning_frame.
(w32font_text_extents): Use owning_frame.
(struct font_callback_data): Add opentype_only field.
(add_font_entity_to_list): Use it to filter fonts.
Don't check against full name.
(w32font_list_internal): New function.
(w32font_list): Use it.
(w32font_match_internal): New function.
(w32font_match): Use it.
(w32font_get_cache, w32font_open, w32font_close, w32font_has_char)
(w32font_encode_char, w32font_text_extents, w32font_draw): Make non-static.