Delay redrawals on palette changes

Build on auto-sync and only mark window dirty on palette changes and let
the event handler do the actual draw.

(cherry picked from commit e823e2308f2a99023032a3966ebb7036a31d305f)

st.c

@@ -1989,7 +1989,7 @@ strhandle(void)
 			else if (xsetcolorname(defaultfg, p))
 				fprintf(stderr, "erresc: invalid foreground color: %s\n", p);
 			else
-				redraw();
+				tfulldirt();
 			return;
 		case 11:
 			if (narg < 2)
@@ -2002,7 +2002,7 @@ strhandle(void)
 			else if (xsetcolorname(defaultbg, p))
 				fprintf(stderr, "erresc: invalid background color: %s\n", p);
 			else
-				redraw();
+				tfulldirt();
 			return;
 		case 12:
 			if (narg < 2)
@@ -2015,7 +2015,7 @@ strhandle(void)
 			else if (xsetcolorname(defaultcs, p))
 				fprintf(stderr, "erresc: invalid cursor color: %s\n", p);
 			else
-				redraw();
+				tfulldirt();
 			return;
 		case 4: /* color set */
 			if (narg < 3)
@@ -2035,7 +2035,7 @@ strhandle(void)
 			} else {
 				if (j == defaultbg)
 					xclearwin();
-				redraw();
+				tfulldirt();
 			}
 			return;
 		}