Make mode line help-echo visible for unibyte buffers.

* src/xdisp.c (decode_mode_spec_coding): Display a space for a unibyte
buffer.

* lisp/bindings.el (mode-line-mule-info-help-echo)
(mode-line-read-only-help-echo, mode-line-modified-help-echo):
New functions.
(mode-line-mule-info, mode-line-modified): Use them.
(mode-line-eol-desc, propertized-buffer-identification):
Consistency fixes for help text.

Fixes: debbugs:11226

2 files changed, 9 insertions, 4 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index c0098445cb8..4eaf2d49f36 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,10 @@
 2012-06-03  Chong Yidong  <cyd@gnu.org>
 
+        * xdisp.c (decode_mode_spec_coding): Display a space for a unibyte
+        buffer (Bug#11226).
+
+2012-06-03  Chong Yidong  <cyd@gnu.org>
+
         * xdisp.c (calc_pixel_width_or_height): Use Fbuffer_local_value.
         (note_mode_line_or_margin_highlight): If there is no help echo,
         use mode-line-default-help-echo.  Handle the case where the mouse
diff --git a/src/xdisp.c b/src/xdisp.c
index 8a1d83dc8e6..f01c86b2a07 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -21012,8 +21012,7 @@ decode_mode_spec_coding (Lisp_Object coding_system, register char *buf, int eol_
 
   if (!VECTORP (val))           /* Not yet decided.  */
     {
-      if (multibyte)
-        *buf++ = '-';
+      *buf++ = multibyte ? '-' : ' ';
       if (eol_flag)
         eoltype = eol_mnemonic_undecided;
       /* Don't mention EOL conversion if it isn't decided.  */
@@ -21026,8 +21025,9 @@ decode_mode_spec_coding (Lisp_Object coding_system, register char *buf, int eol_
       attrs = AREF (val, 0);
       eolvalue = AREF (val, 2);
 
-      if (multibyte)
-        *buf++ = XFASTINT (CODING_ATTR_MNEMONIC (attrs));
+      *buf++ = multibyte
+        ? XFASTINT (CODING_ATTR_MNEMONIC (attrs))
+        : ' ';
 
       if (eol_flag)
         {