Fix signed/unsigned promotion errors involving Emacs_Rectangle

Fix signed/unsigned promotion errors involving Emacs_Rectangle

* src/androidterm.c (android_note_mouse_movement):

* src/pgtkterm.c (note_mouse_movement):

* src/xdisp.c (get_glyph_string_clip_rects, remember_mouse_glyph)
(expose_area, expose_window, gui_intersect_rectangles): Cast
width or height fields in Emacs_Rectangles to int before summing
with or subtracting them from their coordinate fields, as they
are unsigned outside X, and the sign of the coordinates is thus
not preserved.