coq-par-compile: support coqdep warnings from 8.19 onwards

Add user option coq-compile-coqdep-warnings to configure warnings for
Coq 8.19 or later. The default value +module-not-found ensures Proof
General reliably detects missing modules via a coqdep error. This
changes kinds of supersedes the earlier commit
36b1d28 that adapts the coqdep
warning regexp.

CHANGES

@@ -9,6 +9,11 @@ the Git ChangeLog, the GitHub repo https://github.com/ProofGeneral/PG
 
 *** support Coq 8.19
 
+**** New option coq-compile-coqdep-warnings to configure the warning
+     command line argument (-w) of coqdep. The default of this option
+     is +module-not-found to let Proof General reliably detect missing
+     modules as coqdep error.
+
 * Changes of Proof General 4.5 from Proof General 4.4
 
 ** Generic changes

coq/coq-compile-common.el

@@ -522,6 +522,18 @@ or not."
   :type '(repeat regexp)
   :safe (lambda (v) (cl-every #'stringp v)))
 
+(defcustom coq-compile-coqdep-warnings '("+module-not-found")
+  "List of warning options passed to coqdep via `-w` for Coq 8.19 or later.
+List of warning options to be passed to coqdep via command line
+switch `-w`, which is supported from Coq 8.19 onwards. This
+option is ignored for a detected Coq version earlier than 8.19. A
+minus in front of a warning disables the warning, a plus turns
+the warning into an error. This option should contain
+'+module-not-found' to let Proof General reliably detect missing
+modules via an coqdep error."
+  :type '(repeat string)
+  :safe (lambda (v) (cl-every #'stringp v)))
+
 (defcustom coq-coqdep-error-regexp
   (concat "^\\(\\*\\*\\* \\)?Warning: in file .*, library[ \n].* is required "
           "and has not been found")

coq/coq-par-compile.el

@@ -745,14 +745,24 @@ ignored, because they can never participate in a cycle."
     (mapcar (lambda (j) (get j 'src-file)) cycle)))
 
 
-;;; map coq module names to files, using synchronously running coqdep
+;;; map coq module names to files, using coqdep
+
+(defun coq-par-coqdep-warning-arguments ()
+  "Return a fresh list with the warning command line arguments for coqdep.
+Warnings (`-w`) are supported in coqdep from 8.19 onwards.
+Therefore return the empty list for a detected Coq version
+earlier than 8.19."
+  (if (and (coq--post-v818) (consp coq-compile-coqdep-warnings))
+      (list "-w" (mapconcat #'identity coq-compile-coqdep-warnings ","))
+    ()))
 
 (defun coq-par-coqdep-arguments (lib-src-file clpath)
   "Compute the command line arguments for invoking coqdep on LIB-SRC-FILE.
 Argument CLPATH must be `coq-load-path' from the buffer
 that triggered the compilation, in order to provide correct
 load-path options to coqdep."
-  (nconc (coq-coqdep-prog-args clpath
+  (nconc (coq-par-coqdep-warning-arguments)
+         (coq-coqdep-prog-args clpath
                                (file-name-directory lib-src-file)
                                (coq--pre-v85))
          (list lib-src-file)))