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.

1 files changed, 3 insertions, 1 deletions

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;