master 10c680551e: Improve detection of glyphless characters on TTY frames

[Eli Zaretskii]

branch: master
commit 10c680551e899805a6de7360e9b65986fd87df72
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    Improve detection of glyphless characters on TTY frames
    
    * src/term.c (produce_glyphs): If the terminal can report for
    which characters it has glyphs, use that to determine whether
    a given character should be displayed as glyphless.
---
 src/term.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/term.c b/src/term.c
index 4c7a90a577..ddf0e8e2f2 100644
--- a/src/term.c
+++ b/src/term.c
@@ -1632,9 +1632,13 @@ produce_glyphs (struct it *it)
     }
   else
     {
-      Lisp_Object charset_list = FRAME_TERMINAL (it->f)->charset_list;
+      struct terminal *t = FRAME_TERMINAL (it->f);
+      Lisp_Object charset_list = t->charset_list, char_glyph;
 
-      if (char_charset (it->char_to_display, charset_list, NULL))
+      if (char_charset (it->char_to_display, charset_list, NULL)
+         && (char_glyph = terminal_glyph_code (t, it->char_to_display),
+             NILP (char_glyph)
+             || (FIXNUMP (char_glyph) && XFIXNUM (char_glyph) >= 0)))
        {
          it->pixel_width = CHARACTER_WIDTH (it->char_to_display);
          it->nglyphs = it->pixel_width;