patch 8.0.0592: if a job writes to a buffer screen is not updated

Problem:    If a job writes to a buffer and the user is typing a command, the
            screen isn't updated. When a message is displayed the changed
            buffer may cause it to be cleared. (Ramel Eshed)
Solution:   Update the screen and then the command line if the screen didn't
            scroll. Avoid inserting screen lines, as it clears any message.
            Update the status line when the buffer changed.
diff --git a/src/globals.h b/src/globals.h
index 28b71ac..1d67b0d 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -97,6 +97,7 @@
 EXTERN int	redraw_cmdline INIT(= FALSE);	/* cmdline must be redrawn */
 EXTERN int	clear_cmdline INIT(= FALSE);	/* cmdline must be cleared */
 EXTERN int	mode_displayed INIT(= FALSE);	/* mode is being displayed */
+EXTERN int	no_win_do_lines_ins INIT(= FALSE); /* don't insert lines */
 #if defined(FEAT_CRYPT) || defined(FEAT_EVAL)
 EXTERN int	cmdline_star INIT(= FALSE);	/* cmdline is crypted */
 #endif