binfmt: check if binfmt is mounted before applying rules

src/shared/binfmt-util.c

@@ -12,7 +12,7 @@
 #include "missing_magic.h"
 #include "stat-util.h"
 
-static int binfmt_mounted(void) {
+int binfmt_mounted(void) {
         _cleanup_close_ int fd = -EBADF;
         int r;
 

src/shared/binfmt-util.h

@@ -1,4 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
+int binfmt_mounted(void);
 int disable_binfmt(void);