Pacify byte compiler etc. on org-compat, org-macs

Byte-compiler problem reported by Lars Ingebrigtsen in:
https://lists.gnu.org/r/emacs-devel/2022-04/msg01256.html
* lisp/org/org-compat.el (org-at-table.el-p):
Now declared in org-table, not org.
(org-string-collate-lessp): Define the ersatz
org-string-collate-lessp with the same API as the primary form, to
pacify check-declare-file when run on org-macs.
* lisp/org/org-macs.el (org-time-convert-to-integer): Declare.

lisp/org/org-compat.el

@@ -39,7 +39,7 @@
 (declare-function org-calendar-goto-agenda "org-agenda" ())
 (declare-function org-align-tags "org" (&optional all))
 (declare-function org-at-heading-p "org" (&optional ignored))
-(declare-function org-at-table.el-p "org" ())
+(declare-function org-at-table.el-p "org-table" ())
 (declare-function org-element-at-point "org-element" ())
 (declare-function org-element-context "org-element" (&optional element))
 (declare-function org-element-lineage "org-element" (blob &optional types with-self))
@@ -238,7 +238,7 @@ This is a floating point number if the size is too large for an integer."
 (if (fboundp 'string-collate-lessp)
     (defalias 'org-string-collate-lessp
       'string-collate-lessp)
-  (defun org-string-collate-lessp (s1 s2 &rest _)
+  (defun org-string-collate-lessp (s1 s2 &optional _ _)
     "Return non-nil if STRING1 is less than STRING2 in lexicographic order.
 Case is significant."
     (string< s1 s2)))

lisp/org/org-macs.el

@@ -37,6 +37,7 @@
 (declare-function org-mode "org" ())
 (declare-function org-show-context "org" (&optional key))
 (declare-function org-string-collate-lessp "org-compat" (s1 s2 &optional locale ignore-case))
+(declare-function org-time-convert-to-integer "org-compat" (time))
 
 (defvar org-ts-regexp0)
 (defvar ffap-url-regexp)