Make truncate-lines permanently local (bug#15396)

Width of lines relative to display is rarely a function of major mode.
* src/buffer.c (init_buffer_once) <truncate-lines>:
Flag as permanently local.
* lisp/bindings.el (truncate-lines): Add permanent-local property.

2 files changed, 4 insertions, 2 deletions

diff --git a/lisp/bindings.el b/lisp/bindings.el
index 2b664044de8..2bad90351c4 100644
--- a/lisp/bindings.el
+++ b/lisp/bindings.el
@@ -699,7 +699,7 @@ okay.  See `mode-line-format'.")
         buffer-file-format buffer-auto-save-file-format
         buffer-display-count buffer-display-time
         enable-multibyte-characters
-        buffer-file-coding-system))
+        buffer-file-coding-system truncate-lines))
 
 ;; We have base64, md5 and sha1 functions built in now.
 (provide 'base64)
diff --git a/src/buffer.c b/src/buffer.c
index c6f9eb28e25..12a467daae4 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -5134,7 +5134,9 @@ init_buffer_once (void)
   XSETFASTINT (BVAR (&buffer_local_flags, selective_display), idx); ++idx;
   XSETFASTINT (BVAR (&buffer_local_flags, selective_display_ellipses), idx); ++idx;
   XSETFASTINT (BVAR (&buffer_local_flags, tab_width), idx); ++idx;
-  XSETFASTINT (BVAR (&buffer_local_flags, truncate_lines), idx); ++idx;
+  XSETFASTINT (BVAR (&buffer_local_flags, truncate_lines), idx);
+  /* Make this one a permanent local.  */
+  buffer_permanent_local_flags[idx++] = 1;
   XSETFASTINT (BVAR (&buffer_local_flags, word_wrap), idx); ++idx;
   XSETFASTINT (BVAR (&buffer_local_flags, ctl_arrow), idx); ++idx;
   XSETFASTINT (BVAR (&buffer_local_flags, fill_column), idx); ++idx;