fix python artifact build
diff --git a/BUILD b/BUILD
index 201b358..80cda32 100644
--- a/BUILD
+++ b/BUILD
@@ -478,6 +478,7 @@
         "src/core/lib/iomgr/ev_epollsig_linux.c",
         "src/core/lib/iomgr/ev_poll_posix.c",
         "src/core/lib/iomgr/ev_posix.c",
+        "src/core/lib/iomgr/ev_windows.c",
         "src/core/lib/iomgr/exec_ctx.c",
         "src/core/lib/iomgr/executor.c",
         "src/core/lib/iomgr/iocp_windows.c",