add the Thread after errors are handled

- would have ended up with a stale Thread entry
- Thread list access is slock synchronized so it makes
  no difference when we add it

src/core/thread.d

@@ -828,18 +828,6 @@ class Thread
         //       having thread being treated like a daemon thread.
         synchronized( slock )
         {
-            // NOTE: when creating threads from inside a DLL, DllMain(THREAD_ATTACH)
-            //       might be called before ResumeThread returns, but the dll
-            //       helper functions need to know whether the thread is created
-            //       from the runtime itself or from another DLL or the application
-            //       to just attach to it
-            //       as a consequence, the new Thread object is added before actual
-            //       creation of the thread. There should be no problem with the GC
-            //       calling thread_suspendAll, because of the slock synchronization
-            //
-            // VERIFY: does this actually also apply to other platforms?
-            add( this );
-
             version( Windows )
             {
                 if( ResumeThread( m_hndl ) == -1 )
@@ -862,6 +850,18 @@ class Thread
                 if( m_tmach == m_tmach.init )
                     throw new ThreadException( "Error creating thread" );
             }
+
+            // NOTE: when creating threads from inside a DLL, DllMain(THREAD_ATTACH)
+            //       might be called before ResumeThread returns, but the dll
+            //       helper functions need to know whether the thread is created
+            //       from the runtime itself or from another DLL or the application
+            //       to just attach to it
+            //       as a consequence, the new Thread object is added before actual
+            //       creation of the thread. There should be no problem with the GC
+            //       calling thread_suspendAll, because of the slock synchronization
+            //
+            // VERIFY: does this actually also apply to other platforms?
+            add( this );
         }
     }