WIP:

flycheck.el

@@ -5896,15 +5896,10 @@ Return nil (or raise an error if ERROR is non-nil) when CHECKER's
 executable cannot be found, and return a numeric exit status or a
 signal description string otherwise.  CHECKER's input is taken
 from INFILE, and its output is sent to DESTINATION, as in
-`start-file-process'."
+`call-process'."
   (-if-let (executable (flycheck-find-checker-executable checker))
       (condition-case err
-          ;; `start-file-process' runs synchronously, like `call-process',
-          ;; when let bound.`start-file-process' is required to support remote
-          ;; processes. See https://github.com/flycheck/flycheck/pull/1842
-          (let ((rc (apply #'start-file-process
-                           executable infile destination nil args)))
-            rc)
+          (apply #'call-process executable infile destination nil args)
         (error (when error (signal (car err) (cdr err)))))
     (when error
       (user-error "Cannot find `%s' using `flycheck-find-checker-executable'"
@@ -6215,21 +6210,16 @@ and rely on Emacs' own buffering and chunking."
                ;; can easily use pipes.
                (process-connection-type nil))
           ;; We pass do not associate the process with any buffer, by
-          ;; passing nil for the BUFFER argument of `start-file-process'.
+          ;; passing nil for the BUFFER argument of `start-process'.
           ;; Instead, we just remember the buffer being checked in a
           ;; process property (see below).  This neatly avoids all
           ;; side-effects implied by attached a process to a buffer, which
           ;; may cause conflicts with other packages.
           ;;
           ;; See https://github.com/flycheck/flycheck/issues/298 for an
           ;; example for such a conflict.
-          ;;
-          ;; `start-file-process' runs synchronously, like `call-process',
-          ;; when let bound.`start-file-process' is required to support remote
-          ;; processes. See https://github.com/flycheck/flycheck/pull/1842
-          (let ((rc (apply 'start-file-process
-                           (format "flycheck-%s" checker) nil command)))
-            (setq process rc))
+          (setq process (apply 'start-process (format "flycheck-%s" checker)
+                               nil command))
           ;; Process sentinels can be called while sending input to the process.
           ;; We want to record errors raised by process-send before calling
           ;; `flycheck-handle-signal', so initially just accumulate events.