Combine three arguments of curses_putch into one

It will need another parameter for 256-colour support. To avoid having
too many arguments, put glyph colour, background colour and attributes
into a struct and, since to curses library all of that is attributes
that are handled by same function, call the struct "gryph attributes".

curses_putch was also declared in two different headers, remove one of
those declarations.

win/curses/curswins.h

@@ -6,6 +6,11 @@
 #ifndef CURSWIN_H
 # define CURSWIN_H
 
+struct glyph_attributes {
+    int color;
+    int framecolor;
+    int attribute_flags;
+};
 
 /* Global declarations */
 
@@ -27,11 +32,11 @@ void curses_del_wid(winid wid);
 void curs_destroy_all_wins(void);
 #ifdef ENHANCED_SYMBOLS
 void curses_putch(winid wid, int x, int y, int ch,
-                  struct unicode_representation *ur, int color,
-                  int framecolor, int attrs);
+                  struct unicode_representation *ur,
+                  const struct glyph_attributes *attr);
 #else
-void curses_putch(winid wid, int x, int y, int ch, int color,
-                  int framecolor, int attrs);
+void curses_putch(winid wid, int x, int y, int ch,
+                  const struct glyph_attributes *attr);
 #endif
 void curses_get_window_xy(winid wid, int *x, int *y);
 boolean curses_window_has_border(winid wid);