user32: Fix some compilation warnings in 64-bit mode.
diff --git a/dlls/user32/dde_server.c b/dlls/user32/dde_server.c
index e047724..8f43c36 100644
--- a/dlls/user32/dde_server.c
+++ b/dlls/user32/dde_server.c
@@ -800,7 +800,7 @@
     case DDE_FNOTPROCESSED:
 	break;
     }
-    WDML_PostAck(pConv, WDML_SERVER_SIDE, 0, fBusy, fAck, (UINT)pXAct->hMem, 0, 0);
+    WDML_PostAck(pConv, WDML_SERVER_SIDE, 0, fBusy, fAck, (UINT_PTR)pXAct->hMem, 0, 0);
 
     return WDML_QS_HANDLED;
 }