patch 8.2.5057: using gettimeofday() for timeout is very inefficient

Problem:    Using gettimeofday() for timeout is very inefficient.
Solution:   Set a platform dependent timer. (Paul Ollis, closes #10505)
diff --git a/src/proto/os_win32.pro b/src/proto/os_win32.pro
index b3c85b7..706cbd6 100644
--- a/src/proto/os_win32.pro
+++ b/src/proto/os_win32.pro
@@ -83,5 +83,7 @@
 int is_conpty_stable(void);
 int get_conpty_fix_type(void);
 void resize_console_buf(void);
-char * GetWin32Error(void);
+char *GetWin32Error(void);
+void stop_timeout(void);
+const int *start_timeout(long msec);
 /* vim: set ft=c : */