It compiles

patches/server/0143-Entity-fromMobSpawner.patch

@@ -0,0 +1,65 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: BillyGalbreath <Blake.Galbreath@GMail.com>
+Date: Sun, 18 Jun 2017 18:17:05 -0500
+Subject: [PATCH] Entity#fromMobSpawner()
+
+
+diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
+index ffd38defdd9b56b1849a3b4e312de2cff7b964c2..451ba2db54dc1682924fa65283bc88687157322e 100644
+--- a/src/main/java/net/minecraft/world/entity/Entity.java
++++ b/src/main/java/net/minecraft/world/entity/Entity.java
+@@ -393,6 +393,7 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource, S
+     // Spigot end
+     // Paper start
+     protected int numCollisions = 0; // Paper
++    public boolean spawnedViaMobSpawner; // Paper - Yes this name is similar to above, upstream took the better one
+     @javax.annotation.Nullable
+     private org.bukkit.util.Vector origin;
+     @javax.annotation.Nullable
+@@ -2200,6 +2201,10 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource, S
+                 }
+                 nbttagcompound.put("Paper.Origin", this.newDoubleList(origin.getX(), origin.getY(), origin.getZ()));
+             }
++            // Save entity's from mob spawner status
++            if (spawnedViaMobSpawner) {
++                nbttagcompound.putBoolean("Paper.FromMobSpawner", true);
++            }
+             // Paper end
+             return nbttagcompound;
+         } catch (Throwable throwable) {
+@@ -2340,6 +2345,8 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource, S
+                 this.originWorld = originWorld;
+                 origin = new org.bukkit.util.Vector(originTag.getDouble(0), originTag.getDouble(1), originTag.getDouble(2));
+             }
++
++            spawnedViaMobSpawner = nbt.getBoolean("Paper.FromMobSpawner"); // Restore entity's from mob spawner status
+             // Paper end
+ 
+         } catch (Throwable throwable) {
+diff --git a/src/main/java/net/minecraft/world/level/BaseSpawner.java b/src/main/java/net/minecraft/world/level/BaseSpawner.java
+index bd48f49d50709354abc5bcff155b5abb9ab20191..1a5fb001e28997a113ad8133e9dc946206b85c35 100644
+--- a/src/main/java/net/minecraft/world/level/BaseSpawner.java
++++ b/src/main/java/net/minecraft/world/level/BaseSpawner.java
+@@ -167,6 +167,7 @@ public abstract class BaseSpawner {
+                             // Spigot End
+                         }
+ 
++                        entity.spawnedViaMobSpawner = true; // Paper
+                         // CraftBukkit start
+                         if (org.bukkit.craftbukkit.event.CraftEventFactory.callSpawnerSpawnEvent(entity, pos).isCancelled()) {
+                             continue;
+diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
+index 6100b2e718954b40f63ed30ab32e1dea4edba9a6..09cae000b1ff23ab3a0f2a43d83bc7ec05b5623f 100644
+--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
++++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
+@@ -1361,5 +1361,10 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
+         //noinspection ConstantConditions
+         return originVector.toLocation(world);
+     }
++
++    @Override
++    public boolean fromMobSpawner() {
++        return getHandle().spawnedViaMobSpawner;
++    }
+     // Paper end
+ }