bug 2080: long actions after DESTROY

https://bugs.eressea.de/view.php?id=2080
we forgot to set the flags. also added a test for the future.

scripts/tests/e2/movement.lua

@@ -84,3 +84,17 @@ function test_follow_ship()
     assert_equal(2, u1.region.x)
     assert_equal(2, u2.region.x)
 end
+
+function test_dont_move_after_destroy()
+    local r1 = region.create(0, 0, "plain")
+    local r2 = region.create(1, 0, "plain")
+    local f = faction.create("test@example.com", "human", "de")
+    local u = unit.create(f, r1, 1)
+    u.building = building.create(r1, "castle")
+    u:clear_orders()
+    u:add_order("NACH O")
+    u:add_order("ZERSTOERE " .. itoa36(u.building.id))
+    process_orders()
+    assert_equal(r1, u.region)
+    assert_equal(nil, u.building)
+end

src/economy.c

@@ -996,6 +996,9 @@ void economics(region * r)
                 }
             }
         }
+        if (destroyed) {
+            fset(u, UFL_LONGACTION | UFL_NOTMOVING);
+        }
     }
 
 }

src/kernel/build.c

@@ -164,8 +164,7 @@ int destroy_cmd(unit * u, struct order *ord)
     if (s && *s) {
         n = atoi((const char *)s);
         if (n <= 0) {
-            cmistake(u, ord, 288, MSG_PRODUCE);
-            return 0;
+            n = INT_MAX;
         }
     }