Revert "distinguish between options and defaults"

This reverts commit e7804c50.

include/zmq.h

@@ -183,10 +183,8 @@ ZMQ_EXPORT const char *zmq_strerror (int errnum);
 enum zmq_ctx_opts_t {
     /*  Context options                                                       */
     ZMQ_IO_THREADS  = 1,
-    ZMQ_MAX_SOCKETS = 2
-};
+    ZMQ_MAX_SOCKETS = 2,
 
-enum zmq_ctx_defaults_t {
     /*  Default for new contexts                                              */
     ZMQ_IO_THREADS_DFLT  = 1,
     ZMQ_MAX_SOCKETS_DFLT = 1024
@@ -382,10 +380,7 @@ ZMQ_EXPORT int zmq_recviov (void *s, struct iovec *iov, size_t *count, int flags
 enum zmq_poll_types_t {
     ZMQ_POLLIN         = 1,
     ZMQ_POLLOUT        = 2,
-    ZMQ_POLLERR        = 4
-};
-
-enum zmq_poll_defaults_t {
+    ZMQ_POLLERR        = 4,
     ZMQ_POLLITEMS_DFLT = 16
 };