patch 9.0.0308: when cmdheight is zero the attention prompt doesn't show
Problem: When cmdheight is zero the attention prompt doesn't show.
Solution: Do not use the message window for a prompt.
diff --git a/src/proto/message.pro b/src/proto/message.pro
index bea3016..f0bd4f3 100644
--- a/src/proto/message.pro
+++ b/src/proto/message.pro
@@ -24,6 +24,7 @@
void set_keep_msg(char_u *s, int attr);
void set_keep_msg_from_hist(void);
int use_message_window(void);
+void dont_use_message_window(void);
void msg_start(void);
void msg_starthere(void);
void msg_putchar(int c);