add Aura for motherzombies where all zombies have increased health regen

src/zr/infect.inc

@@ -1157,6 +1157,24 @@ bool:InfectIsClientInfected(client)
     return g_bZombie[client];
 }
 
+/**
+ * Returns if a client is infected and a motherzombie.
+ *
+ * @param client    The client index.
+ * @return          True if the client has been infected as motherzombie, false otherwise.
+ */
+bool:InfectIsClientMotherZombie(client)
+{
+    // If client is invalid, then stop.
+    if (!ZRIsClientValid(client))
+    {
+        return false;
+    }
+
+    // Return client's motherzombie flag.
+    return g_bInfectMotherLast[client];
+}
+
 /**
  * Returns if a client is a human.
  *