Include paths.h.

Include paths.h.

Support background stipple, and search path for bitmap files:

(x_set_icon_type): Pass x_bitmap_icon 2nd arg as Lisp_Object.
(x_icon_type): Return a Lisp_Object.

(x_destroy_bitmap, x_reference_bitmap): Take frame as arg.  Callers changed.
(struct x_bitmap_record): New fields height, width, depth.
(x_create_bitmap_from_data): Fill in those fields.
(x_bitmap_height, x_bitmap_width, x_bitmap_pixmap): New functions.
(x_create_bitmap_from_file): Arg FILE is now a Lisp_Object.
Search Vbitmap_file_path for it.  Fill in new fields.
(syms_of_xfns): Set up Vbitmap_file_path.