Set SO_REUSEPORT on the Art-Net socket so a console on the same machine can share port 6454

On macOS and the BSDs a wildcard UDP port is shared only when every socket
sets SO_REUSEPORT. QLC+ (Qt sets it) already bound to 6454 made BlenderDMX's
bind fail with EADDRINUSE, so a console and the visualiser could not run on
one machine. SO_REUSEADDR alone is not enough there; Linux keeps working as
before, and the option is skipped where the platform lacks it.

Author: CristianDeluxe

artnet.py

@@ -27,6 +27,11 @@
     socket,
 )
 
+try:
+    from socket import SO_REUSEPORT
+except ImportError:  # Windows
+    SO_REUSEPORT = None
+
 import bpy
 
 from .data import DMX_Data
@@ -105,6 +110,12 @@ def __init__(self, ip_addr, *args, **kwargs):
         self._socket = socket(AF_INET, SOCK_DGRAM)
         self._socket.setsockopt(SOL_SOCKET, SO_BROADCAST, 1)
         self._socket.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
+        if SO_REUSEPORT is not None:
+            # On macOS and the BSDs a wildcard UDP port is shared only when
+            # every socket sets SO_REUSEPORT; without it a console already
+            # bound to 6454 on the same machine (QLC+, Qt sets it) makes
+            # this bind fail with EADDRINUSE.
+            self._socket.setsockopt(SOL_SOCKET, SO_REUSEPORT, 1)
         try:
             self._socket.bind((ip_addr, ARTNET_PORT))
         except OSError as e: