Replace zmqconfig.h by a simple zmqutil.

zmqconfig.h is currently not really needed anywhere, except that
it declares zmqError (which is then defined in
zmqnotificationinterface.cpp).  Note in particular that there is
no need to conditionally include zmq.h only if ZMQ is enabled, because
the place in the core code where the ZMQ library itself is included
(init.cpp) is conditional already on that.

This commit removes zmqconfig.h and replaces it by a much simpler
zmqutil.h library for zmqError.  The definition of the function is
moved to the matching (newly created) zmqutil.cpp.

src/Makefile.am

@@ -262,10 +262,10 @@ BITCOIN_CORE_H = \
   walletinitinterface.h \
   warnings.h \
   zmq/zmqabstractnotifier.h \
-  zmq/zmqconfig.h\
   zmq/zmqnotificationinterface.h \
   zmq/zmqpublishnotifier.h \
-  zmq/zmqrpc.h
+  zmq/zmqrpc.h \
+  zmq/zmqutil.h
 
 
 obj/build.h: FORCE
@@ -344,7 +344,8 @@ libbitcoin_zmq_a_SOURCES = \
   zmq/zmqabstractnotifier.cpp \
   zmq/zmqnotificationinterface.cpp \
   zmq/zmqpublishnotifier.cpp \
-  zmq/zmqrpc.cpp
+  zmq/zmqrpc.cpp \
+  zmq/zmqutil.cpp
 endif
 
 

src/zmq/zmqabstractnotifier.cpp

@@ -4,6 +4,8 @@
 
 #include <zmq/zmqabstractnotifier.h>
 
+#include <cassert>
+
 const int CZMQAbstractNotifier::DEFAULT_ZMQ_SNDHWM;
 
 CZMQAbstractNotifier::~CZMQAbstractNotifier()

src/zmq/zmqabstractnotifier.h

@@ -5,13 +5,13 @@
 #ifndef BITCOIN_ZMQ_ZMQABSTRACTNOTIFIER_H
 #define BITCOIN_ZMQ_ZMQABSTRACTNOTIFIER_H
 
-#include <zmq/zmqconfig.h>
-
 #include <util/memory.h>
 
 #include <memory>
+#include <string>
 
 class CBlockIndex;
+class CTransaction;
 class CZMQAbstractNotifier;
 
 using CZMQNotifierFactory = std::unique_ptr<CZMQAbstractNotifier> (*)();

src/zmq/zmqnotificationinterface.cpp

@@ -4,15 +4,13 @@
 
 #include <zmq/zmqnotificationinterface.h>
 #include <zmq/zmqpublishnotifier.h>
+#include <zmq/zmqutil.h>
+
+#include <zmq.h>
 
 #include <validation.h>
 #include <util/system.h>
 
-void zmqError(const char *str)
-{
-    LogPrint(BCLog::ZMQ, "zmq: Error: %s, errno=%s\n", str, zmq_strerror(errno));
-}
-
 CZMQNotificationInterface::CZMQNotificationInterface() : pcontext(nullptr)
 {
 }

src/zmq/zmqpublishnotifier.cpp

@@ -2,13 +2,15 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <zmq/zmqpublishnotifier.h>
+
 #include <chain.h>
 #include <chainparams.h>
+#include <rpc/server.h>
 #include <streams.h>
-#include <zmq/zmqpublishnotifier.h>
-#include <validation.h>
 #include <util/system.h>
-#include <rpc/server.h>
+#include <validation.h>
+#include <zmq/zmqutil.h>
 
 #include <zmq.h>
 

src/zmq/zmqutil.cpp

@@ -0,0 +1,14 @@
+// Copyright (c) 2014-2018 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <zmq/zmqutil.h>
+
+#include <logging.h>
+
+#include <zmq.h>
+
+void zmqError(const char* str)
+{
+    LogPrint(BCLog::ZMQ, "zmq: Error: %s, errno=%s\n", str, zmq_strerror(errno));
+}

src/zmq/zmqutil.h

@@ -0,0 +1,10 @@
+// Copyright (c) 2014-2018 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_ZMQ_ZMQUTIL_H
+#define BITCOIN_ZMQ_ZMQUTIL_H
+
+void zmqError(const char* str);
+
+#endif // BITCOIN_ZMQ_ZMQUTIL_H