Problem: zmq_threadstart name not distinguished

Solution: name it ZMQapp instead of ZMQbg, as it's created by the
application

src/thread.hpp

@@ -74,7 +74,7 @@ class thread_t
 
     //  Creates OS thread. 'tfn' is main thread function. It'll be passed
     //  'arg' as an argument.
-    void start (thread_fn *tfn_, void *arg_, const char *name_ = "0MQ");
+    void start (thread_fn *tfn_, void *arg_, const char *name_);
 
     //  Returns whether the thread was started, i.e. start was called.
     bool get_started () const;

src/zmq_utils.cpp

@@ -84,7 +84,7 @@ void *zmq_threadstart (zmq_thread_fn *func_, void *arg_)
 {
     zmq::thread_t *thread = new (std::nothrow) zmq::thread_t;
     alloc_assert (thread);
-    thread->start (func_, arg_);
+    thread->start (func_, arg_, "ZMQapp");
     return thread;
 }