Fix dual birth ai

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "aise"
-version = "2.21.3"
+version = "2.21.4"
 authors = ["Markus Heikkinen <ittevien@gmail.com>"]
 
 [lib]

src/lib.rs

@@ -458,6 +458,21 @@ unsafe extern fn step_order_hook(u: *mut c_void, orig: unsafe extern fn(*mut c_v
     }
     if let Some(ai) = temp_ai {
         (*unit.0).ai = ai;
+        // Add ai for dual birthed units
+        if unit.id().flags() & 0x400 != 0 {
+            // Bw inserts shown units at second pos for some reason..
+            if let Some(other) = unit::active_units().nth(1) {
+                // This gets actually checked several times since the birth order lasts a few
+                // frames, but it should be fine.
+                if other.id() == unit.id() && (*other.0).ai.is_null() {
+                    if other.player() == unit.player() {
+                        let region = ai::ai_region(other.player(), other.position())
+                            .expect("Unit out of bounds??");
+                        ai::add_military_ai(other, region, false);
+                    }
+                }
+            }
+        }
     }
 }
 

src/list.rs

@@ -87,6 +87,16 @@ impl ListEntry for bw::MilitaryAi {
     }
 }
 
+impl ListEntry for bw::Unit {
+    unsafe fn next(x: *mut Self) -> *mut *mut Self {
+        &mut (*x).next
+    }
+
+    unsafe fn prev(x: *mut Self) -> *mut *mut Self {
+        &mut (*x).prev
+    }
+}
+
 pub struct ListIter<T: ListEntry>(pub *mut T);
 
 impl<T: ListEntry> Iterator for ListIter<T> {