Migrate to Emacs_GC

Migrate to Emacs_GC

* ../src/xfaces.c (x_create_gc, x_free_gc):

* ../src/pgtkterm.h (struct pgtk_output, struct pgtk_output):

* ../src/pgtkterm.c (x_set_cursor_gc, x_set_mouse_face_gc)
(x_setup_relief_color, x_draw_image_foreground_1)
(x_draw_image_foreground)
(pgtk_cr_draw_image, pgtk_draw_fringe_bitmap)
(pgtk_begin_cr_clip, pgtk_set_cr_source_with_gc_foreground)
(pgtk_set_cr_source_with_gc_background):

* ../src/pgtkgui.h:

* ../src/dispextern.h (struct glyph_string): clean up XGCValues  emulation

XGCValues, GC 廃止。

Emacs_GC に統一。