Merge pull request #64 from GreatFruitOmsk/fix-msvc2015

Fix configure failure on 32-bit MSVC.

CMakeLists.txt

@@ -117,10 +117,15 @@ check_include_files(windows.h ZMQ_HAVE_WINDOWS)
 check_include_files(sys/uio.h ZMQ_HAVE_UIO)
 check_include_files(sys/eventfd.h ZMQ_HAVE_EVENTFD)
 
-check_library_exists(ws2_32 WSAStartup "" HAVE_WS2_32)
-check_library_exists(ws2 WSAStartup "" HAVE_WS2)
-check_library_exists(rpcrt4 UuidCreate "" HAVE_RPCRT4)
-check_library_exists(iphlpapi GetNetworkParams "" HAVE_IPHLAPI)
+if(MSVC)
+  # Force stdcall convention
+  set(CMAKE_REQUIRED_FLAGS "/Gz")
+endif()
+check_library_exists(ws2_32 WSAGetLastError "" HAVE_WS2_32)
+check_library_exists(ws2 WSAGetLastError "" HAVE_WS2)
+check_library_exists(rpcrt4 RpcErrorClearInformation "" HAVE_RPCRT4)
+check_library_exists(iphlpapi GetAdapterOrderMap "" HAVE_IPHLAPI)
+unset(CMAKE_REQUIRED_FLAGS)
 
 check_cxx_symbol_exists(SO_PEERCRED sys/socket.h ZMQ_HAVE_SO_PEERCRED)
 check_cxx_symbol_exists(LOCAL_PEERCRED sys/socket.h ZMQ_HAVE_LOCAL_PEERCRED)