Fix the unexec build on MS-Windows

* src/buffer.c (init_buffer) [USE_MMAP_FOR_BUFFERS]: If dumped
with unexec, be sure to map new memory also for the " prin1"
buffer.  For the reasons and discussion, see
https://lists.gnu.org/archive/html/emacs-devel/2021-04/msg01401.html.

1 files changed, 9 insertions, 2 deletions

diff --git a/src/buffer.c b/src/buffer.c
index 8e33162989b..9e417bf555c 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -5390,17 +5390,24 @@ init_buffer (void)
          recorded by temacs, that cannot be used by the dumped Emacs.
          We map new memory for their text here.
 
-         Implementation note: the buffers we carry from temacs are:
+         Implementation notes: the buffers we carry from temacs are:
          " prin1", "*scratch*", " *Minibuf-0*", "*Messages*", and
          " *code-conversion-work*".  They are created by
          init_buffer_once and init_window_once (which are not called
-         in the dumped Emacs), and by the first call to coding.c routines.  */
+         in the dumped Emacs), and by the first call to coding.c
+         routines.  Since FOR_EACH_LIVE_BUFFER only walks the buffers
+         in Vbuffer_alist, any buffer we carry from temacs that is
+         not in the alist (a.k.a. "magic invisible buffers") should
+         be handled here explicitly.  */
       FOR_EACH_LIVE_BUFFER (tail, buffer)
         {
           struct buffer *b = XBUFFER (buffer);
           b->text->beg = NULL;
           enlarge_buffer_text (b, 0);
         }
+      /* The " prin1" buffer is not in Vbuffer_alist.  */
+      XBUFFER (Vprin1_to_string_buffer)->text->beg = NULL;
+      enlarge_buffer_text (XBUFFER (Vprin1_to_string_buffer), 0);
     }
 #endif /* USE_MMAP_FOR_BUFFERS */