Port double-line underlines to GUI systems

Port double-line underlines to GUI systems

* src/xterm.c (x_get_scale_factor): Replace display in first
argument with a pointer to dpyinfo.
(x_draw_underwave): Adjust to match.
(x_draw_glyph_string): Implement double-line underlines.

* src/androidterm.c (android_get_scale_factor)
(android_draw_glyph_string):

* src/haikuterm.c (haiku_draw_text_decoration):

* src/nsterm.m (ns_draw_text_decoration):

* src/pgtkterm.c (pgtk_draw_glyph_string):

* src/w32term.c (w32_draw_glyph_string): Synchronize with X.

* src/xfaces.c (realize_gui_face): Enable `double-line' on
window systems.