Use STRLEN in two places
diff --git a/src/tmpfiles/tmpfiles.c b/src/tmpfiles/tmpfiles.c
index 46098c2..82cda5d 100644
--- a/src/tmpfiles/tmpfiles.c
+++ b/src/tmpfiles/tmpfiles.c
@@ -1307,7 +1307,7 @@
         r = action(i, fd, st);
 
         if (S_ISDIR(st->st_mode)) {
-                char procfs_path[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
+                char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
                 _cleanup_closedir_ DIR *d = NULL;
                 struct dirent *de;