patch 7.4.1319
Problem:    Tests fail on MS-Windows and on Unix with GUI.
Solution:   Fix unregistering.
diff --git a/src/proto/channel.pro b/src/proto/channel.pro
index f748052..e6e050c 100644
--- a/src/proto/channel.pro
+++ b/src/proto/channel.pro
@@ -22,10 +22,10 @@
 void channel_clear(channel_T *channel);
 void channel_free_all(void);
 int channel_get_id(void);
-void channel_read(channel_T *channel, int what, char *func);
+void channel_read(channel_T *channel, int which, char *func);
 char_u *channel_read_block(channel_T *channel);
 int channel_read_json_block(channel_T *channel, int id, typval_T **rettv);
-channel_T *channel_fd2channel(sock_T fd, int *what);
+channel_T *channel_fd2channel(sock_T fd, int *whichp);
 int channel_send(channel_T *channel, char_u *buf, char *fun);
 int channel_poll_setup(int nfd_in, void *fds_in);
 int channel_poll_check(int ret_in, void *fds_in);