--- a/lisp/ChangeLog	Wed Dec 12 00:42:48 2007 +0100
+++ b/lisp/ChangeLog	Fri Dec 14 14:13:02 2007 +0100
@@ -1,3 +1,21 @@
+2007-12-14  Aidan Kehoe  <kehoea@parhasard.net>
+
+	* process.el (substitute-env-vars):
+	Merge an example from GNU's docstring. 
+	* process.el (setenv):	
+	Pass nil as the default abbrev table to the #'read-from-minibuffer
+	call, instead of passing the current value of the variable. Bug
+	introduced by an incorrect sync from GNU by Ben; reported by
+	Thomas Mittelstaedt in 47626712.40609@cadenas.de.
+
+	Document the #'set-time-zone-rule call when TZ is set. Push the
+	old value on to the beginning of setenv-history. (Both merged from
+	GNU.) Document that we don't do the coding-system frobbing at this
+	level that GNU does. 
+
+	Provide a commented-out, sample implementation of GNU's
+	#'environment; document why I think we shouldn't include it.
+
 2007-12-11  Aidan Kehoe  <kehoea@parhasard.net>
 
 	* mule/latin.el :

--- a/lisp/process.el	Wed Dec 12 00:42:48 2007 +0100
+++ b/lisp/process.el	Fri Dec 14 14:13:02 2007 +0100
@@ -25,7 +25,7 @@
 ;; Boston, MA 02111-1307, USA.
 
 ;;; Synched up with: FSF 19.30, except for setenv/getenv (synched with FSF
-;;; 21.0.105).
+;;; 21.2.1).
 
 ;;; Authorship:
 
@@ -542,8 +542,10 @@
 `$FOO' where FOO is an environment variable name means to substitute
 the value of that variable.  The variable name should be terminated
 with a character not a letter, digit or underscore; otherwise, enclose
-the entire variable name in braces.  Use `$$' to insert a single
-dollar sign."
+the entire variable name in braces.  For instance, in `ab$cd-x',
+`$cd' is treated as an environment variable.
+
+Use `$$' to insert a single dollar sign."
   (let ((start 0))
     (while (string-match
 	    ;; XEmacs change - FSF use their rx macro to generate this regexp
@@ -575,19 +577,40 @@
 Interactively, the current value (if any) of the variable
 appears at the front of the history list when you type in the new value.
 
-This function works by modifying `process-environment'."
+This function works by modifying `process-environment'.
+
+As a special case, setting variable `TZ' calls `set-time-zone-rule' as
+a side-effect."
   (interactive
    (if current-prefix-arg
        (list (read-envvar-name "Clear environment variable: " 'exact) nil t)
-     (let ((var (read-envvar-name "Set environment variable: " nil)))
+     (let* ((var (read-envvar-name "Set environment variable: " nil))
+            (value (getenv var)))
+       (when value
+         (push value setenv-history))
        ;; Here finally we specify the args to call setenv with.
        (list var (read-from-minibuffer (format "Set %s to value: " var)
 				       nil nil nil 'setenv-history
-				       (getenv var))))))
+                                       ;; XEmacs change; don't specify a
+                                       ;; default. (Nor an abbrev table.)
+                                       )))))
   (if unset 
       (setq value nil)
     (if substitute-env-vars
 	(setq value (substitute-env-vars value))))
+
+  ;; GNU fuck around with coding systems here. We do it at a much lower
+  ;; level; an equivalent of the following code of Handa's would be
+  ;; worthwhile here, though:
+
+; (let ((codings (find-coding-systems-string (concat variable value))))
+;   (unless (or (eq 'undecided (car codings))
+;               (memq (coding-system-base locale-coding-system) codings))
+;     (error "Can't encode `%s=%s' with `locale-coding-system'"
+;            variable (or value "")))))
+
+  ;; But then right now our find-coding-systems analogue is in packages.
+
   (if (string-match "=" variable)
       (error "Environment variable name `%s' contains `='" variable)
     (let ((pattern (concat "\\`" (regexp-quote (concat variable "="))))
@@ -626,6 +649,25 @@
 ;       (message "%s" (if value value "Not set")))
 ;     value))
 
+
+;; GNU have an #'environment function here, as of 2007-12-14. If someone
+;; actually uses it in the wild, this would suffice as an implementation:
+
+; (defun environment (&optional frame) 
+;   "Return a list of environment variables with their values.
+; Each entry in the list is a string of the form NAME=VALUE.
+; 
+; Optional argument FRAME is ignored, for GNU compatibility.
+; 
+; Non-ASCII characters look like Mojibake (that is, they are unreadable.)"
+;   (loop
+;     for entry in process-environment
+;     collect (encode-coding-string entry 'native)))
+; 
+
+;; but we shouldn't encourage that sort of ugliness and needless backwards
+;; incompatibility.
+
 (provide 'env) ;; Yuck.  Formerly the above were in env.el, which did this
 	       ;; provide.