fix no net compilation on zephyr (#19399)

Co-authored-by: Jaremy J. Creechley <[email protected]>
(cherry picked from commit dc8ac66)

lib/posix/posix_other.nim

@@ -399,16 +399,20 @@ elif defined(zephyr):
     const Sockaddr_max_length* = 24
   elif defined(net_raw):
     const Sockaddr_max_length* = 20
-  else:
+  elif defined(net_ipv4):
     const Sockaddr_max_length* = 8
+  else:
+    const Sockaddr_max_length* = 255 # just for compilation purposes
+
   const Sockaddr_un_path_length* = Sockaddr_max_length
   # Zephyr is heavily customizable so it's easy to get to a state  
   # where Nim & Zephyr IPv6 settings are out of sync, causing painful runtime failures. 
-  {.emit: ["NIM_STATIC_ASSERT(NET_SOCKADDR_MAX_SIZE == ",
-      Sockaddr_max_length,
-      ",\"NET_SOCKADDR_MAX_SIZE and Sockaddr_max_length size mismatch!",
-      " Check that Nim and Zephyr IPv4/IPv6 settings match.",
-      " Try adding -d:net_ipv6 to enable IPv6 for Nim on Zephyr.\" );"].}
+  when defined(net_ipv4) or defined(net_ipv6) or defined(net_raw):
+    {.emit: ["NIM_STATIC_ASSERT(NET_SOCKADDR_MAX_SIZE == ",
+        Sockaddr_max_length,
+        ",\"NET_SOCKADDR_MAX_SIZE and Sockaddr_max_length size mismatch!",
+        " Check that Nim and Zephyr IPv4/IPv6 settings match.",
+        " Try adding -d:net_ipv6 to enable IPv6 for Nim on Zephyr.\" );"].}
 elif defined(freertos) or defined(lwip):
   const Sockaddr_max_length* = 14
   const Sockaddr_un_path_length* = 108