Problem: generates incompatible libzmq.so.3.1.0

See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=743508

The ABI in fact changed in two significant ways, one with inproc
connects, and one with socket monitoring

Solution: generate libzmq.so.4.0.0 library instead.

This change should be backported to zeromq-4.x

.gitignore

@@ -90,6 +90,7 @@ tests/test_connect_rid
 tests/test_srcfd
 tests/test_stream_disconnect
 tests/test_proxy_chain
+tests/test_bind_src_address
 tests/test*.log
 tests/test*.trs
 src/platform.hpp*

configure.ac

@@ -29,10 +29,10 @@ AC_SUBST(PACKAGE_VERSION)
 # ZeroMQ versions 2.1.x: 1:0:0 (ABI version 1)
 # ZeroMQ version 3.0: 2:0:0 (ABI version 2)
 # ZeroMQ version 3.1: 3:0:0 (ABI version 3)
-# ZeroMQ version 4.0: 4:0:1 (ABI version 4)
+# ZeroMQ version 4.0: 4:0:0 (ABI version 4)
 #
 # libzmq -version-info current:revision:age
-LTVER="4:0:1"
+LTVER="4:0:0"
 AC_SUBST(LTVER)
 
 # Take a copy of original flags