introduce support for coloring the frame behind a map location

Also includes support by paxed for polearm targeting using the
frame color.

Also renames USE_TILES to TILES_IN_GLYPHMAP which is a more
accurate description.

Not all window interfaces have full support for the color framing
of the background square yet.

MS-DOS needs further work (to bring it to both VESA and VGA, with
and without tiles.

Windows GUI is missing support.

X11 and Qt have been started, but may require further refinement.

include/wintty.h

@@ -92,6 +92,7 @@ struct DisplayDesc {
     short curx, cury; /* current cursor position on the screen */
 #ifdef TEXTCOLOR
     int color; /* current color */
+    uint32 framecolor; /* current background color */
 #endif
     int attrs;         /* attributes in effect */
     int toplin;        /* flag for topl stuff */
@@ -153,8 +154,8 @@ E void tty_shutdown(void);
 #endif
 E int xputc(int);
 E void xputs(const char *);
-#if defined(SCREEN_VGA) || defined(SCREEN_8514)
-E void xputg(const glyph_info *);
+#if defined(SCREEN_VGA) || defined(SCREEN_8514) || defined(SCREEN_VESA)
+E void xputg(const glyph_info *, const glyph_info *);
 #endif
 E void cl_end(void);
 E void clear_screen(void);
@@ -188,6 +189,7 @@ E void term_end_raw_bold(void);
 #ifdef TEXTCOLOR
 E void term_end_color(void);
 E void term_start_color(int color);
+E void term_start_bgcolor(int color);
 #endif /* TEXTCOLOR */
 #ifdef ENHANCED_SYMBOLS
 extern void term_start_24bitcolor(struct unicode_representation *);