Helm: Fix Strawberry integration.

.emacs.d/lisp/init-helm.el

@@ -300,10 +300,11 @@ With prefix argument, UPDATE the databases with custom uptions thanks to the
                 "strawberry"
               "EMMS"))
    (lambda (_candidate)
-     (let ((adder)))
      (or (when (executable-find "strawberry")
            (apply #'call-process
-                  "strawberry" nil nil nil (helm-marked-candidates)))))
+                  "strawberry" nil nil nil (helm-marked-candidates)))
+         (when (require 'emms nil 'noerror)
+           (mapc 'emms-add-directory-tree (helm-marked-candidates)))))
    source
    (lambda (candidate)
      (or (file-directory-p candidate)