Move gensym to core Elisp

* doc/lispref/symbols.texi (Creating Symbols): Mention gensym right
after make-symbol.
* etc/NEWS: Mention.
* lisp/emacs-lisp/cl-macs.el (cl--gensym-counter): Alias to
gensym-counter.
(cl-gensym): Alias to gensym.
* lisp/emacs-lisp/cl.el: Remove gensym from list of aliases.
* lisp/emacs-lisp/edebug.el (edebug-make-enter-wrapper):
* lisp/emacs-lisp/ert-x.el (ert-with-message-capture):
(ert--expand-should-1, ert--expand-should):
(ert--should-error-handle-error):
* lisp/emacs-lisp/generator.el (cps--gensym):
* lisp/emacs-lisp/gv.el (setf):
* lisp/emacs-lisp/inline.el (inline--do-letlisteval):
* lisp/emacs-lisp/pcase.el (pcase--make-docstring, pcase-dolist):
(pcase--funcall, pcase--u1): Use gensym.
* lisp/subr.el (gensym-counter): New variable.
(gensym): New function, assimilated from cl-lib.

1 files changed, 14 insertions, 0 deletions

diff --git a/lisp/subr.el b/lisp/subr.el
index 2ad52f6a638..ebb8b53b502 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -280,6 +280,20 @@ without silencing all errors."
 
 ;;;; Basic Lisp functions.
 
+(defvar gensym-counter 0
+  "Number used to construct the name of the next symbol created by `gensym'.")
+
+(defun gensym (&optional prefix)
+  "Return a new uninterned symbol.
+The name is made by appending `gensym-counter' to PREFIX.
+PREFIX can be a string, and defaults to \"G\".
+If PREFIX is a number, it replaces the value of `gensym-counter'."
+  (let ((pfix (if (stringp prefix) prefix "G"))
+        (num (if (integerp prefix) prefix
+               (prog1 gensym-counter
+                 (setq gensym-counter (1+ gensym-counter))))))
+    (make-symbol (format "%s%d" pfix num))))
+
 (defun ignore (&rest _ignore)
   "Do nothing and return nil.
 This function accepts any number of arguments, but ignores them."