master c86a302: Merge from origin/emacs-28

[Ken Brown]

branch: master
commit c86a3029ec56ef54d6a23e1c5bed0d554c4b0c2b
Merge: 96ac514 6ba4e3b
Author: Ken Brown <kbrown@cornell.edu>
Commit: Ken Brown <kbrown@cornell.edu>

    Merge from origin/emacs-28
    
    6ba4e3b78c Drop support for native compilation on 32-bit Cygwin
    7e15ee5bc9 ; * doc/emacs/help.texi (Help Mode): Improve indexing.
---
 configure.ac        | 11 +++++++++++
 doc/emacs/help.texi | 10 ++++++----
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/configure.ac b/configure.ac
index 86928c8..33e7037 100644
--- a/configure.ac
+++ b/configure.ac
@@ -486,6 +486,7 @@ OPTION_DEFAULT_ON([zlib],[don't compile with zlib 
decompression support])
 OPTION_DEFAULT_ON([modules],[don't compile with dynamic modules support])
 OPTION_DEFAULT_ON([threads],[don't compile with elisp threading support])
 OPTION_DEFAULT_OFF([native-compilation],[compile with Emacs Lisp native 
compiler support])
+OPTION_DEFAULT_OFF([cygwin32-native-compilation],[use native compilation on 
32-bit Cygwin])
 
 AC_ARG_WITH([file-notification],[AS_HELP_STRING([--with-file-notification=LIB],
  [use a file notification library (LIB one of: yes, inotify, kqueue, gfile, 
w32, no)])],
@@ -3839,6 +3840,16 @@ source on this site:
 HAVE_NATIVE_COMP=no
 LIBGCCJIT_LIBS=
 LIBGCCJIT_CFLAGS=
+if test "$canonical" = i686-pc-cygwin; then
+  if test "${with_cygwin32_native_compilation}" = yes; then
+    with_native_compilation=yes
+  elif test "${with_native_compilation}" != no; then
+    AC_MSG_ERROR([Native compilation is not supported on 32-bit Cygwin.
+If you really want to try it anyway, use the configure option
+'--with-cygwin32-native-compilation'.])
+  fi
+fi
+
 if test "${with_native_compilation}" != "no"; then
     if test "${HAVE_PDUMPER}" = no; then
        AC_MSG_ERROR(['--with-native-compilation' requires 
'--with-dumping=pdumper'])
diff --git a/doc/emacs/help.texi b/doc/emacs/help.texi
index 0cc92d1..20a9d8b 100644
--- a/doc/emacs/help.texi
+++ b/doc/emacs/help.texi
@@ -443,11 +443,13 @@ alphabetical order, change the variable
 
 @node Help Mode
 @section Help Mode Commands
+@findex help-mode
+@cindex help mode
 
-  Help buffers provide the same commands as View mode (@pxref{View
-Mode}); for instance, @key{SPC} scrolls forward, and @key{DEL} or
-@kbd{S-@key{SPC}} scrolls backward.  A few special commands are also
-provided:
+  Help buffers have Help mode as their major mode.  Help mode provides
+the same commands as View mode (@pxref{View Mode}); for instance,
+@key{SPC} scrolls forward, and @key{DEL} or @kbd{S-@key{SPC}} scrolls
+backward.  It also provides a few special commands:
 
 @table @kbd
 @item @key{RET}