Avoid using subr-x.el function in files.el

* lisp/files.el (file-size-human-readable): Open code string-empty-p
call.  This was the single occurrence of a subr-x.el function in
files.el, which does not (yet) load subr-x.el.

diff --git a/lisp/files.el b/lisp/files.el
index a431be8d5d8f698a84fef0b726faabfeec0aa510..05150ac0214e1658d4f4467d0101ab5337dd7563 100644 (file)
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -1396,7 +1396,7 @@ in all cases, since that is the standard symbol for byte."
                  "%.1f%s%s"
                "%.0f%s%s")
              file-size
-              (if (string-empty-p prefixed-unit) "" (or space ""))
+              (if (string= prefixed-unit "") "" (or space ""))
               prefixed-unit))))
 
 (defcustom mounted-file-systems