updated for version 7.3.187

Problem:    The RISC OS port has obvious errors and is not being maintained.
Solution:   Remove the RISC OS files and code.

src/gui.h

@@ -52,10 +52,6 @@
 # include <SegLoad.h>*/
 #endif
 
-#ifdef RISCOS
-# include "gui_riscos.h"
-#endif
-
 #ifdef FEAT_GUI_PHOTON
 # include <Ph.h>
 # include <Pt.h>
@@ -151,7 +147,7 @@
 #define DRAW_BOLD		0x02	/* draw bold text */
 #define DRAW_UNDERL		0x04	/* draw underline text */
 #define DRAW_UNDERC		0x08	/* draw undercurl text */
-#if defined(RISCOS) || defined(FEAT_GUI_GTK)
+#if defined(FEAT_GUI_GTK)
 # define DRAW_ITALIC		0x10	/* draw italic text */
 #endif
 #define DRAW_CURSOR		0x20	/* drawing block cursor (win32) */
@@ -219,9 +215,6 @@ typedef struct GuiScrollbar
 #ifdef FEAT_GUI_MAC
     ControlHandle id;		/* A handle to the scrollbar */
 #endif
-#ifdef RISCOS
-    int		id;		/* Window handle of scrollbar window */
-#endif
 #ifdef FEAT_GUI_PHOTON
     PtWidget_t	*id;
 #endif
@@ -450,14 +443,6 @@ typedef struct Gui
     int		visibility;	    /* Is window partially/fully obscured? */
 #endif
 
-#ifdef RISCOS
-    int		window_handle;
-    char_u	*window_title;
-    int		window_title_size;
-    int		fg_colour;		/* in 0xBBGGRR format */
-    int		bg_colour;
-#endif
-
 #ifdef FEAT_GUI_PHOTON
     PtWidget_t	*vimWindow;		/* PtWindow */
     PtWidget_t	*vimTextArea;		/* PtRaw */