Fix Bug#22814

* src/doc.c (get_doc_string): Raise an error in case too many
files are open.  (Bug#22814)

src/doc.c

@@ -126,6 +126,9 @@ get_doc_string (Lisp_Object filepos, bool unibyte, bool definition)
   fd = emacs_open (name, O_RDONLY, 0);
   if (fd < 0)
     {
+      if ((errno == EMFILE) || (errno == ENFILE))
+	report_file_error ("Read error on documentation file", file);
+
 #ifndef CANNOT_DUMP
       if (!NILP (Vpurify_flag))
 	{