autotools: move checking for zmq library to common area in configure.ac

* Fixes #6679

* Tested with --disable-zmq
* Tested with and without pkgconfig
* Tested with and without zmq installed

Signed-off-by: Johnathan Corgan <johnathan@corganlabs.com>

configure.ac

@@ -693,6 +693,16 @@ if test x$use_pkgconfig = xyes; then
       if test x$use_qr != xno; then
         BITCOIN_QT_CHECK([PKG_CHECK_MODULES([QR], [libqrencode], [have_qrencode=yes], [have_qrencode=no])])
       fi
+
+      if test "x$use_zmq" = "xyes"; then
+        PKG_CHECK_MODULES([ZMQ],[libzmq >= 4],
+          [AC_DEFINE([ENABLE_ZMQ],[1],[Define to 1 to enable ZMQ functions])],
+          [AC_DEFINE([ENABLE_ZMQ],[0],[Define to 1 to enable ZMQ functions])
+           AC_MSG_WARN([libzmq version 4.x or greater not found, disabling])
+           use_zmq=no])
+      else
+          AC_DEFINE_UNQUOTED([ENABLE_ZMQ],[0],[Define to 1 to enable ZMQ functions])
+      fi
     ]
   )
 else
@@ -705,6 +715,20 @@ else
   AC_CHECK_HEADER([openssl/ssl.h],, AC_MSG_ERROR(libssl headers missing),)
   AC_CHECK_LIB([ssl],         [main],SSL_LIBS=-lssl, AC_MSG_ERROR(libssl missing))
 
+  if test "x$use_zmq" = "xyes"; then
+     AC_CHECK_HEADER([zmq.h],
+       [AC_DEFINE([ENABLE_ZMQ],[1],[Define to 1 to enable ZMQ functions])],
+       [AC_MSG_WARN([zmq.h not found, disabling zmq support])
+        use_zmq=no
+        AC_DEFINE([ENABLE_ZMQ],[0],[Define to 1 to enable ZMQ functions])])
+     AC_CHECK_LIB([zmq],[zmq_ctx_shutdown],ZMQ_LIBS=-lzmq,
+       [AC_MSG_WARN([libzmq >= 4.0 not found, disabling zmq support])
+        use_zmq=no
+        AC_DEFINE([ENABLE_ZMQ],[0],[Define to 1 to enable ZMQ functions])])
+  else
+    AC_DEFINE_UNQUOTED([ENABLE_ZMQ],[0],[Define to 1 to enable ZMQ functions])
+  fi
+
   BITCOIN_QT_CHECK(AC_CHECK_LIB([protobuf] ,[main],[PROTOBUF_LIBS=-lprotobuf], BITCOIN_QT_FAIL(libprotobuf not found)))
   if test x$use_qr != xno; then
     BITCOIN_QT_CHECK([AC_CHECK_LIB([qrencode], [main],[QR_LIBS=-lqrencode], [have_qrencode=no])])
@@ -863,20 +887,6 @@ if test x$bitcoin_enable_qt != xno; then
   fi
 fi
 
-# conditional search for and use libzmq
-AC_MSG_CHECKING([whether to build ZMQ support])
-if test "x$use_zmq" = "xyes"; then
-  AC_MSG_RESULT([yes])
-  PKG_CHECK_MODULES([ZMQ],[libzmq >= 4],
-    [AC_DEFINE([ENABLE_ZMQ],[1],[Define to 1 to enable ZMQ functions])],
-    [AC_DEFINE([ENABLE_ZMQ],[0],[Define to 1 to enable ZMQ functions])
-     AC_MSG_WARN([libzmq version 4.x or greater not found, disabling])
-     use_zmq=no])
-else
-  AC_MSG_RESULT([no, --disable-zmq used])
-  AC_DEFINE_UNQUOTED([ENABLE_ZMQ],[0],[Define to 1 to enable ZMQ functions])
-fi
-
 AM_CONDITIONAL([ENABLE_ZMQ], [test "x$use_zmq" = "xyes"])
 
 AC_MSG_CHECKING([whether to build test_bitcoin])