lisp/emacs-lisp/comp-cstr.el: Fix bootstrap

* lisp/emacs-lisp/comp-cstr.el: Remove redundant require of `cl-macs`
and add missing require of `cl-extra`.

* lisp/emacs-lisp/cl-generic.el: Improve warning message.
* lisp/emacs-lisp/cl-extra.el (cl--print-table): Remove redundant arg.

lisp/emacs-lisp/cl-extra.el

@@ -872,7 +872,7 @@ PROPLIST is a list of the sort returned by `symbol-plist'.
                       "%s")
               formats)
         (cl-incf col (+ col-space (aref cols i))))
-      (let ((format (mapconcat #'identity (nreverse formats) "")))
+      (let ((format (mapconcat #'identity (nreverse formats))))
         (insert (apply #'format format
                        (mapcar (lambda (str) (propertize str 'face 'italic))
                                header))

lisp/emacs-lisp/cl-generic.el

@@ -272,7 +272,7 @@ DEFAULT-BODY, if present, is used as the body of a default method.
               (list
                (macroexp-warn-and-return
                 (format "Non-symbol arguments to cl-defgeneric: %s"
-                        (mapconcat #'prin1-to-string nonsymargs ""))
+                        (mapconcat #'prin1-to-string nonsymargs " "))
                 nil nil nil nonsymargs)))))
          next-head)
     (while (progn (setq next-head (car-safe (car options-and-methods)))

lisp/emacs-lisp/cl-lib.el

@@ -533,7 +533,12 @@ If ALIST is non-nil, the new pairs are prepended to it."
 (unless (load "cl-loaddefs" 'noerror 'quiet)
   ;; When bootstrapping, cl-loaddefs hasn't been built yet!
   (require 'cl-macs)
-  (require 'cl-seq))
+  (require 'cl-seq)
+  ;; FIXME: Arguably we should also load `cl-extra', except that this
+  ;; currently causes more bootstrap troubles, and `cl-extra' is
+  ;; rarely used, so instead we explicitly (require 'cl-extra) at
+  ;; those rare places where we do need it.
+  )
 
 (defun cl--old-struct-type-of (orig-fun object)
   (or (and (vectorp object) (> (length object) 0)

lisp/emacs-lisp/comp-cstr.el

@@ -36,7 +36,7 @@
 ;;; Code:
 
 (require 'cl-lib)
-(require 'cl-macs)
+(require 'cl-extra) ;HACK: For `cl-find-class' when `cl-loaddefs' is missing.
 
 (defconst comp--typeof-builtin-types (mapcar (lambda (x)
                                                (append x '(t)))