cmake: Set HAVE_GETADDRINFO if we have libsocket.

This fixes the build on Solaris.

ConfigureChecks.cmake

@@ -122,7 +122,8 @@ if (UNIX)
         # libsocket (Solaris)
         check_library_exists(socket getaddrinfo "" HAVE_LIBSOCKET)
         if (HAVE_LIBSOCKET)
-          set(CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES} socket)
+            set(HAVE_GETADDRINFO 1)
+            set(CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES} socket)
         endif (HAVE_LIBSOCKET)
 
         # libnsl/inet_pton (Solaris)