asyncdispatch: for NuttX, add destructor to clear global dispatcher. (#21432)

* asyncdispatch: for NuttX, add destructor to clear global dispatcher using atexit().

Signed-off-by: Takeyoshi Kikuchi <kikuchi@centurysys.co.jp>

* std: exitprocs: remove "when defined(nuttx)" block.

Signed-off-by: Takeyoshi Kikuchi <kikuchi@centurysys.co.jp>

---------

Signed-off-by: Takeyoshi Kikuchi <kikuchi@centurysys.co.jp>

lib/pure/asyncdispatch.nim

@@ -1216,6 +1216,15 @@ else:
 
   var gDisp{.threadvar.}: owned PDispatcher ## Global dispatcher
 
+  when defined(nuttx):
+    import std/exitprocs
+
+    proc cleanDispatcher() {.noconv.} =
+      gDisp = nil
+
+    proc addFinalyzer() =
+      addExitProc(cleanDispatcher)
+
   proc setGlobalDispatcher*(disp: owned PDispatcher) =
     if not gDisp.isNil:
       assert gDisp.callbacks.len == 0
@@ -1225,6 +1234,8 @@ else:
   proc getGlobalDispatcher*(): PDispatcher =
     if gDisp.isNil:
       setGlobalDispatcher(newDispatcher())
+      when defined(nuttx):
+        addFinalyzer()
     result = gDisp
 
   proc getIoHandler*(disp: PDispatcher): Selector[AsyncData] =
@@ -1591,7 +1602,7 @@ else:
       owned(Future[tuple[address: string, client: AsyncFD]]) =
     var retFuture = newFuture[tuple[address: string,
         client: AsyncFD]]("acceptAddr")
-    proc cb(sock: AsyncFD): bool =
+    proc cb(sock: AsyncFD): bool {.gcsafe.} =
       result = true
       var sockAddress: Sockaddr_storage
       var addrLen = sizeof(sockAddress).SockLen

lib/std/exitprocs.nim

@@ -45,6 +45,7 @@ proc callClosures() {.noconv.} =
       case fun.kind
       of kClosure: fun.fun1()
       of kNoconv: fun.fun2()
+    gFuns.setLen(0)
 
 template fun() =
   if gFuns.len == 0: