borg-compile: Account for native-compile's return value

It returns the filename, not t, on success.  In case of failure it
does not return and signals an error instead, but we now wrap that
function so that we can increase the failure count.

Author: tarsius

borg.el

@@ -537,7 +537,9 @@ then also activate the clone using `borg-activate'."
       (setq borg-compile-function
             (if (functionp borg--compile-natively)
                 borg--compile-natively
-              'native-compile)))
+              #'borg--native-compile)))
+    (when (eq borg-compile-function #'native-compile)
+      (setq borg-compile-function #'borg--native-compile))
     (if build
         (dolist (cmd build)
           (message "  Running `%s'..." cmd)
@@ -746,8 +748,9 @@ then also activate the clone using `borg-activate'."
                     ('no-byte-compile
                      (message "Compiling %s...skipped" file)
                      skip-count)
-                    ('t file-count)
-                    (_  fail-count))))
+                    ((or 't (pred stringp))
+                     file-count)
+                    (_ fail-count))))
                (unless (equal dir last-dir)
                  (setq last-dir dir)
                  (cl-incf dir-count))))))))
@@ -792,6 +795,10 @@ then also activate the clone using `borg-activate'."
                      t))
         (ignore-errors (delete-file file))))))
 
+(defun borg--native-compile (file)
+  (with-demoted-errors "borg--native-compile: %S"
+    (native-compile file)))
+
 ;;; Assimilation
 
 (defun borg-assimilate (package url &optional partially)