patch 8.1.1049: when user tries to exit with CTRL-C message is confusing

Problem:    When user tries to exit with CTRL-C message is confusing.
Solution:   Only mention ":qa!" when there is a changed buffer. (closes #4163)

src/normal.c

@@ -8886,7 +8886,12 @@ nv_esc(cmdarg_T *cap)
 #endif
 		&& !VIsual_active
 		&& no_reason)
+	{
+	    if (anyBufIsChanged())
 		msg(_("Type  :qa!  and press <Enter> to abandon all changes and exit Vim"));
+	    else
+		msg(_("Type  :qa  and press <Enter> to exit Vim"));
+	}
 
 	/* Don't reset "restart_edit" when 'insertmode' is set, it won't be
 	 * set again below when halfway a mapping. */

src/proto/undo.pro

@@ -25,6 +25,7 @@ void u_clearline(void);
 void u_undoline(void);
 void u_blockfree(buf_T *buf);
 int bufIsChanged(buf_T *buf);
+int anyBufIsChanged(void);
 int bufIsChangedNotTerm(buf_T *buf);
 int curbufIsChanged(void);
 void u_eval_tree(u_header_T *first_uhp, list_T *list);

src/testdir/test_normal.vim

@@ -1,5 +1,7 @@
 " Test for various Normal mode commands
 
+source shared.vim
+
 func Setup_NewWindow()
   10new
   call setline(1, range(1,100))
@@ -2542,3 +2544,13 @@ func Test_nv_hat_count()
 
   %bwipeout!
 endfunc
+
+func Test_message_when_using_ctrl_c()
+  exe "normal \<C-C>"
+  call assert_match("Type  :qa  and press <Enter> to exit Vim", Screenline(&lines))
+  new
+  cal setline(1, 'hi!')
+  exe "normal \<C-C>"
+  call assert_match("Type  :qa!  and press <Enter> to abandon all changes and exit Vim", Screenline(&lines))
+  bwipe!
+endfunc

src/undo.c

@@ -3530,6 +3530,19 @@ bufIsChanged(buf_T *buf)
     return bufIsChangedNotTerm(buf);
 }
 
+/*
+ * Return TRUE if any buffer has changes.  Also buffers that are not written.
+ */
+    int
+anyBufIsChanged(void)
+{
+    buf_T *buf;
+
+    FOR_ALL_BUFFERS(buf)
+	if (bufIsChanged(buf))
+	    return TRUE;
+}
+
 /*
  * Like bufIsChanged() but ignoring a terminal window.
  */

src/version.c

@@ -775,6 +775,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1049,
 /**/
     1048,
 /**/