Implement chghost capability

Interaction with extended-join doesn't yet work correctly, because ZNC
doesn't keep track of everyone's real names

include/znc/Client.h

@@ -119,6 +119,7 @@ class CClient : public CIRCSocket {
     bool HasExtendedJoin() const { return m_bExtendedJoin; }
     bool HasNamesx() const { return m_bNamesx; }
     bool HasUHNames() const { return m_bUHNames; }
+    bool HasChgHost() const { return m_bChgHost; }
     bool IsAway() const { return m_bAway; }
     bool HasServerTime() const { return m_bServerTime; }
     bool HasBatch() const { return m_bBatch; }
@@ -289,6 +290,7 @@ class CClient : public CIRCSocket {
     bool m_bExtendedJoin;
     bool m_bNamesx;
     bool m_bUHNames;
+    bool m_bChgHost;
     bool m_bAway;
     bool m_bServerTime;
     bool m_bBatch;

include/znc/IRCSock.h

@@ -131,6 +131,7 @@ class CIRCSock : public CIRCSocket {
     unsigned int GetMaxNickLen() const { return m_uMaxNickLen; }
     EChanModeArgs GetModeType(char cMode) const;
     char GetPermFromMode(char cMode) const;
+    char GetModeFromPerm(char cPerm) const;
     const std::map<char, EChanModeArgs>& GetChanModes() const {
         return m_mceChanModes;
     }
@@ -177,6 +178,7 @@ class CIRCSock : public CIRCSocket {
     bool OnActionMessage(CActionMessage& Message);
     bool OnAwayMessage(CMessage& Message);
     bool OnCapabilityMessage(CMessage& Message);
+    bool OnChgHostMessage(CChgHostMessage& Message);
     bool OnCTCPMessage(CCTCPMessage& Message);
     bool OnErrorMessage(CMessage& Message);
     bool OnInviteMessage(CMessage& Message);

include/znc/Message.h

@@ -67,6 +67,7 @@ class CMessage {
         Action,
         Away,
         Capability,
+        ChgHost,
         CTCP,
         Error,
         Invite,
@@ -121,6 +122,7 @@ class CMessage {
      */
     VCString GetParamsSplit(unsigned int uIdx, unsigned int uLen = -1) const;
     void SetParams(const VCString& vsParams);
+    void SetParams(VCString&& vsParams);
 
     /// @deprecated use GetParamsColon() instead.
     CString GetParams(unsigned int uIdx, unsigned int uLen = -1) const
@@ -333,4 +335,13 @@ class CTopicMessage : public CTargetMessage {
 };
 REGISTER_ZNC_MESSAGE(CTopicMessage);
 
+class CChgHostMessage : public CMessage {
+  public:
+    CString GetNewIdent() const { return GetParam(0); }
+    void SetNewIdent(const CString& sIdent) { SetParam(0, sIdent); }
+    CString GetNewHost() const { return GetParam(1); }
+    void SetNewHost(const CString& sHost) { SetParam(1, sHost); }
+};
+REGISTER_ZNC_MESSAGE(CChgHostMessage);
+
 #endif  // !ZNC_MESSAGE_H