use custom struct for stat watcher.

src/gevent/libuv/_corecffi_cdef.c

@@ -289,4 +289,11 @@ static void _gevent_generic_callback0(uv_handle_t* handle); // no extra args
 static void _gevent_generic_callback1(uv_handle_t* handle, int arg); // one extra args. Everything will funnel through this
 static void _gevent_poll_callback2(uv_handle_t* handle, int status, int events);
 static void _gevent_fs_event_callback3(uv_handle_t* handle, const char* filename, int events, int status);
-static void _gevent_fs_poll_callback3(uv_handle_t* handle, int status, const uv_stat_t* prev, const uv_stat_t* curr);
+
+typedef struct _gevent_fs_poll_s {
+	uv_fs_poll_t handle;
+	uv_stat_t curr;
+	uv_stat_t prev;
+} gevent_fs_poll_t;
+
+static void _gevent_fs_poll_callback3(void* handle, int status, const uv_stat_t* prev, const uv_stat_t* curr);

src/gevent/libuv/_corecffi_source.c

@@ -44,10 +44,35 @@ static void _gevent_fs_event_callback3(uv_handle_t* handle, const char* filename
 {
 	_gevent_generic_callback1(handle, status < 0 ? status : events);
 }
+/*
+typedef struct {
+	uv_fs_poll_t handle;
+	uv_stat_t curr;
+	uv_stat_t prev;
+} gevent_fs_poll_t;
+*/
 
-static void _gevent_fs_poll_callback3(uv_handle_t* handle, int status, const uv_stat_t* prev, const uv_stat_t* curr)
+typedef struct _gevent_fs_poll_s {
+	uv_fs_poll_t handle;
+	uv_stat_t curr;
+	uv_stat_t prev;
+} gevent_fs_poll_t;
+
+static void _gevent_fs_poll_callback3(void* handlep, int status, const uv_stat_t* prev, const uv_stat_t* curr)
 {
 	// stat pointers are valid for this callback only.
-	// Will need a custom callback for this or somehow be able to pass
-	// copied data up.
+	// if given, copy them into our structure, where they can be reached
+	// from python, just like libev's watcher does, before calling
+	// the callback.
+	if(status < 0) {
+		return;
+	}
+
+	gevent_fs_poll_t* handle = (gevent_fs_poll_t*)handlep;
+	assert(status == 0);
+
+	handle->curr = *curr;
+	handle->prev = *prev;
+
+	_gevent_generic_callback1((uv_handle_t*)handle, 0);
 }