Move CBlockLocator to core.h

As CBlockLocator is a P2P data structure, and independent from the
validation logic, it can be moved to core.

src/core.h

@@ -661,4 +661,38 @@ public:
     void print() const;
 };
 
+
+/** Describes a place in the block chain to another node such that if the
+ * other node doesn't have the same branch, it can find a recent common trunk.
+ * The further back it is, the further before the fork it may be.
+ */
+struct CBlockLocator
+{
+    std::vector<uint256> vHave;
+
+    CBlockLocator() {}
+
+    CBlockLocator(const std::vector<uint256>& vHaveIn)
+    {
+        vHave = vHaveIn;
+    }
+
+    IMPLEMENT_SERIALIZE
+    (
+        if (!(nType & SER_GETHASH))
+            READWRITE(nVersion);
+        READWRITE(vHave);
+    )
+
+    void SetNull()
+    {
+        vHave.clear();
+    }
+
+    bool IsNull()
+    {
+        return vHave.empty();
+    }
+};
+
 #endif

src/main.h

@@ -22,7 +22,6 @@ class CBlock;
 class CBlockIndex;
 class CKeyItem;
 class CReserveKey;
-class CBlockLocator;
 
 class CAddress;
 class CInv;
@@ -1047,43 +1046,6 @@ extern CChain chainActive;
 
 
 
-/** Describes a place in the block chain to another node such that if the
- * other node doesn't have the same branch, it can find a recent common trunk.
- * The further back it is, the further before the fork it may be.
- */
-class CBlockLocator
-{
-protected:
-    std::vector<uint256> vHave;
-public:
-    CBlockLocator() {}
-
-    CBlockLocator(const std::vector<uint256>& vHaveIn)
-    {
-        vHave = vHaveIn;
-    }
-
-    IMPLEMENT_SERIALIZE
-    (
-        if (!(nType & SER_GETHASH))
-            READWRITE(nVersion);
-        READWRITE(vHave);
-    )
-
-    void SetNull()
-    {
-        vHave.clear();
-    }
-
-    bool IsNull()
-    {
-        return vHave.empty();
-    }
-
-    friend class CChain;
-};
-
-