curses: correctly pass the color pair to setcchar()

The current code does not correctly pass the color pair information to
setcchar(), it instead always passes zero. This results in the curses
output always being in white on black.

This patch fixes this by using PAIR_NUMBER() to retrieve the color pair
number from the chtype value, and then passes that value as an argument
to setcchar().

Signed-off-by: Matthew Kilgore <mattkilgore12@gmail.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Tested-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Message-id: 20191004035338.25601-3-mattkilgore12@gmail.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

ui/curses.c

@@ -77,12 +77,14 @@ static void curses_update(DisplayChangeListener *dcl,
         for (x = 0; x < width; x++) {
             chtype ch = line[x] & A_CHARTEXT;
             chtype at = line[x] & A_ATTRIBUTES;
+            short color_pair = PAIR_NUMBER(line[x]);
+
             ret = getcchar(&vga_to_curses[ch], wch, &attrs, &colors, NULL);
             if (ret == ERR || wch[0] == 0) {
                 wch[0] = ch;
                 wch[1] = 0;
             }
-            setcchar(&curses_line[x], wch, at, 0, NULL);
+            setcchar(&curses_line[x], wch, at, color_pair, NULL);
         }
         mvwadd_wchnstr(screenpad, y, 0, curses_line, width);
     }