Fix shadow of previous local

Fix the build failure in https://github.com/flatpak/flatpak/pull/3853

bubblewrap.c

@@ -1600,7 +1600,7 @@ parse_args_recurse (int          *argcp,
           if (argc < 2)
             die ("--remount-ro takes one argument");
 
-          SetupOp *op = setup_op_new (SETUP_REMOUNT_RO_NO_RECURSIVE);
+          op = setup_op_new (SETUP_REMOUNT_RO_NO_RECURSIVE);
           op->dest = argv[1];
 
           argv++;

configure.ac

@@ -70,6 +70,7 @@ dnl Keep this in sync with ostree, except remove -Werror=declaration-after-state
 CC_CHECK_FLAGS_APPEND([WARN_CFLAGS], [CFLAGS], [\
         -pipe \
         -Wall \
+        -Werror=shadow \
 	-Werror=empty-body \
 	-Werror=strict-prototypes \
 	-Werror=missing-prototypes \