vim-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 vim/vim#4163)
https://github.com/vim/vim/commit/a84a3dd6635fcd2e07f510cba6a999585dcc381a

vim-patch:8.1.1052: test for CTRL-C message sometimes fails

Problem:    test for CTRL-C message sometimes fails
Solution:   Make sure there are no changed buffers.
https://github.com/vim/vim/commit/553e5a5c568e7d175b65b0472cd6d9843b25f4c8

vim-patch:8.1.1053: warning for missing return statement

Problem:    Warning for missing return statement. (Dominique Pelle)
Solution:   Add return statement.
https://github.com/vim/vim/commit/d6c3f1fa2b5e1dd7dc87cf608d72b84ad696b58f

1 files changed, 13 insertions, 0 deletions

diff --git a/src/nvim/undo.c b/src/nvim/undo.c
index c9b0d96866..1305e013ad 100644
--- a/src/nvim/undo.c
+++ b/src/nvim/undo.c
@@ -2961,10 +2961,23 @@ static char_u *u_save_line(linenr_T lnum)
 ///
 /// @return true if the buffer has changed
 bool bufIsChanged(buf_T *buf)
+  FUNC_ATTR_WARN_UNUSED_RESULT
 {
   return !bt_dontwrite(buf) && (buf->b_changed || file_ff_differs(buf, true));
 }
 
+// Return true if any buffer has changes.  Also buffers that are not written.
+bool anyBufIsChanged(void)
+  FUNC_ATTR_WARN_UNUSED_RESULT
+{
+  FOR_ALL_BUFFERS(buf) {
+    if (bufIsChanged(buf)) {
+      return true;
+    }
+  }
+  return false;
+}
+
 /// Check if the 'modified' flag is set, or 'ff' has changed (only need to
 /// check the first character, because it can only be "dos", "unix" or "mac").
 /// "nofile" and "scratch" type buffers are considered to always be unchanged.