--- a/lisp/ChangeLog	Sat Mar 14 00:42:46 2015 +0000
+++ b/lisp/ChangeLog	Sat Mar 14 01:16:45 2015 +0000
@@ -1,3 +1,8 @@
+2015-03-14  Aidan Kehoe  <kehoea@parhasard.net>
+
+	* cus-start.el (all): Describe help-event-list for Custom.
+	* keydefs.el (help-event-list): Initialise it.
+
 2015-03-12  Aidan Kehoe  <kehoea@parhasard.net>
 
 	* simple.el (append-message): Be more careful about saving a

--- a/lisp/cus-start.el	Sat Mar 14 00:42:46 2015 +0000
+++ b/lisp/cus-start.el	Sat Mar 14 01:16:45 2015 +0000
@@ -152,6 +152,7 @@
 	     (focus-follows-mouse x boolean)
 	     (help-char keyboard (choice character
 					 (sexp :tag "Single key specifier")))
+	     (help-event-list keyboard (repeat (sexp :format "%v")))
 	     (max-lisp-eval-depth limits integer)
 	     (max-specpdl-size limits integer)
 	     (meta-prefix-char keyboard character)

--- a/lisp/keydefs.el	Sat Mar 14 00:42:46 2015 +0000
+++ b/lisp/keydefs.el	Sat Mar 14 01:16:45 2015 +0000
@@ -162,6 +162,8 @@
 ;; do backspace.
 (define-key global-map '(meta ??) 'help-command)
 
+(setq help-event-list '(help f1 (meta ??)))
+
 ;; FSFmacs indent.el
 
 ;;(define-key global-map "\t" 'self-insert-command)

--- a/man/ChangeLog	Sat Mar 14 00:42:46 2015 +0000
+++ b/man/ChangeLog	Sat Mar 14 01:16:45 2015 +0000
@@ -1,3 +1,8 @@
+2015-03-14  Aidan Kehoe  <kehoea@parhasard.net>
+
+	* lispref/help.texi (Help Functions):
+	Document help-event-list, just added.
+
 2015-02-23  Mike Kupfer  <mike.kupfer@xemacs.org>
 
 	* internals/internals.texi (The Redisplay Mechanism):

--- a/man/lispref/help.texi	Sat Mar 14 00:42:46 2015 +0000
+++ b/man/lispref/help.texi	Sat Mar 14 01:16:45 2015 +0000
@@ -584,6 +584,13 @@
 subcommands of the prefix key.
 @end defvar
 
+@defvar help-event-list
+This variable provides a means to specify other characters that should
+act in the same way @code{help-char} does, with regard to
+@code{help-form} and supplying help. It is usually set to include
+@kbd{f1}, so that this key is also treated as giving help.
+@end defvar
+
 @defvar help-form
 If this variable is non-@code{nil}, its value is a form to evaluate
 whenever the character @code{help-char} is read.  If evaluating the form

--- a/src/ChangeLog	Sat Mar 14 00:42:46 2015 +0000
+++ b/src/ChangeLog	Sat Mar 14 01:16:45 2015 +0000
@@ -1,3 +1,21 @@
+2015-03-14  Aidan Kehoe  <kehoea@parhasard.net>
+
+	Add support for GNU's help-event-list here, useful for accepting
+	F1 and C-h as the help character at the same time.
+	* event-stream.c:
+	* event-stream.c (echo_key_event):
+	Be better about calculation, comments here, in passing.
+	* event-stream.c (help_char_p): New.
+	* event-stream.c (execute_help_form):
+	There's no need to reset the command builder here; the code that
+	did relied on zero-termination, which we can't anymore, and did
+	not actually discard the help character. Remove this.
+	* event-stream.c (Fnext_event): Use help_char_p ().
+	* event-stream.c (command_builder_find_leaf_no_jit_binding):
+	Use help_char_p ().
+	* event-stream.c (vars_of_event_stream):
+	Make help-event-list available.
+
 2015-03-14  Aidan Kehoe  <kehoea@parhasard.net>
 
 	* .gdbinit.in.in (Lisp): lrecord_type_lcrecord_list is specific to

--- a/src/event-stream.c	Sat Mar 14 00:42:46 2015 +0000
+++ b/src/event-stream.c	Sat Mar 14 01:16:45 2015 +0000
@@ -197,10 +197,13 @@
    of the last-command-event. */
 Lisp_Object Vlast_command_event_time;
 
-/* Character to recognize as the help char.  */
+/* Key specifier to recognize as the help char.  */
 Lisp_Object Vhelp_char;
 
-/* Form to execute when help char is typed.  */
+/* List of other key specifiers that work in the same way as Vhelp_char. */
+Lisp_Object Vhelp_event_list;
+
+/* Form to execute when Vhelp_char or one of Vhelp_event_list is typed.  */
 Lisp_Object Vhelp_form;
 
 /* Command to run when the help character follows a prefix key.  */
@@ -650,7 +653,7 @@
   len = eilen (buf);
 
   if (NILP (command_builder->echo_buf) ||
-      (len + buf_fill_pointer + 4 > XSTRING_LENGTH (command_builder->echo_buf)))
+      (len + buf_fill_pointer + 3 > XSTRING_LENGTH (command_builder->echo_buf)))
     {
       eifree (buf);
       return;
@@ -665,7 +668,7 @@
   sledgehammer_check_ascii_begin (command_builder->echo_buf);
 
   command_builder->echo_buf_end = buf_fill_pointer + eilen (buf);
-  /* *Not* including the trailing " - ". */
+  /* Including the first space of the trailing " - ". */
   command_builder->echo_buf_fill_pointer = buf_fill_pointer + len + 1;
   eifree (buf);
 }
@@ -790,6 +793,27 @@
   return Qnil;
 }
 
+/* Return true if should recognize C as "the help character".  */
+static Boolint
+help_char_p (Lisp_Object event)
+{
+  if (event_matches_key_specifier_p (event, Vhelp_char))
+    {
+      return 1;
+    }
+
+  {
+    EXTERNAL_LIST_LOOP_2 (key_sequence, Vhelp_event_list)
+      {
+        if (event_matches_key_specifier_p (event, key_sequence))
+          {
+            return 1;
+          }
+      }
+  }
+  return 0;
+}
+
 static void
 execute_help_form (struct command_builder *command_builder,
                    Lisp_Object event)
@@ -797,18 +821,13 @@
   /* This function can GC */
   Lisp_Object help = Qnil;
   int speccount = specpdl_depth ();
-  Bytecount buf_fill_pointer = command_builder->echo_buf_fill_pointer;
-  Bytecount buf_end = command_builder->echo_buf_end;
-  Lisp_Object echo = ((buf_fill_pointer <= 0) ? Qnil
-                      : Fcopy_sequence (command_builder->echo_buf));
-
-  struct gcpro gcpro1, gcpro2;
-  GCPRO2 (echo, help);
+
+  struct gcpro gcpro1;
+  GCPRO1 (help);
 
   record_unwind_protect (Feval,
                          list2 (Qset_window_configuration,
                                 call0 (Qcurrent_window_configuration)));
-  reset_key_echo (command_builder, 1);
 
   help = IGNORE_MULTIPLE_VALUES (Feval (Vhelp_form));
   if (STRINGP (help))
@@ -835,17 +854,11 @@
   if (event_matches_key_specifier_p (event, make_char (' ')))
     {
       /* Discard next key if it is a space */
-      reset_key_echo (command_builder, 1);
+      /* No need to reset the key echo here. */
+      /* reset_key_echo (command_builder, 1); */
       Fnext_command_event (event, Qnil);
     }
 
-  command_builder->echo_buf_fill_pointer = buf_fill_pointer;
-  command_builder->echo_buf_end = buf_end;
-
-  if (buf_fill_pointer > 0)
-    {
-      command_builder->echo_buf = echo;
-    }
   UNGCPRO;
 }
 
@@ -2379,8 +2392,7 @@
      the help form and swallow this character.  Note that
      execute_help_form() calls Fnext_command_event(), which calls this
      function, as well as Fdispatch_event.  */
-  if (!NILP (Vhelp_form) &&
-      event_matches_key_specifier_p (event, Vhelp_char))
+  if (!NILP (Vhelp_form) && help_char_p (event))
     {
       /* temporarily reenable quit checking here, because we could get stuck */
       Vquit_flag = Qnil; /* see begin_dont_check_for_quit() */
@@ -3396,8 +3408,8 @@
     }
 
   /* help-char is `auto-bound' in every keymap */
-  if (!NILP (Vprefix_help_command) &&
-      event_matches_key_specifier_p (builder->most_current_event, Vhelp_char))
+  if (!NILP (Vprefix_help_command)
+      && help_char_p (builder->most_current_event))
     return Vprefix_help_command;
 
   return Qnil;
@@ -5154,18 +5166,25 @@
   Vthis_command_properties = Qnil;
 
   DEFVAR_LISP ("help-char", &Vhelp_char /*
-Character to recognize as meaning Help.
+Key specifier to recognize as meaning Help.
 When it is read, do `(eval help-form)', and display result if it's a string.
-If the value of `help-form' is nil, this char can be read normally.
-This can be any form recognized as a single key specifier.
-The help-char cannot be a negative number in XEmacs.
+If the value of `help-form' is nil, this key can be read normally.
+This can be any form recognized as a single key specifier; see
+`event-matches-key-specifier-p' and `define-key'.
 */ );
   Vhelp_char = make_char (8); /* C-h */
 
+  DEFVAR_LISP ("help-event-list", &Vhelp_event_list /*
+List of extra key specifiers to recognize as meaning Help.
+These are in addition to the value of `help-char', which see.  They function
+in the same way, and can equally be suppressed by binding `help-form' to nil.
+*/ );
+  Vhelp_event_list = Qnil;
+
   DEFVAR_LISP ("help-form", &Vhelp_form /*
-Form to execute when character help-char is read.
+Form to execute when `help-char' or an element of `help-event-list' is read.
 If the form returns a string, that string is displayed.
-If `help-form' is nil, the help char is not recognized.
+If `help-form' is nil, `help-char' and `help-event-list' are ignored.
 */ );
   Vhelp_form = Qnil;