fix: define FUSE_USE_VERSION before including fuse.h in xattr.h

xattr.h included fuse.h without ltfs_fuse_version.h. libfuse 2 headers
default to an old API level when FUSE_USE_VERSION is undefined, but
libfuse 3 headers reject it, breaking every translation unit that
pulls in xattr.h. The release branch received the same change as part
of the FreeBSD build fix (b3e3355).

Author: matejk

src/libltfs/xattr.h

@@ -66,7 +66,9 @@ extern "C" {
 #include "libltfs/arch/freebsd/xattr.h"
 #endif
 
-#include "fuse.h"
+#include "libltfs/ltfs_fuse_version.h"
+#include <fuse.h>
+
 #include "ltfs.h"
 
 #define LTFS_PRIVATE_PREFIX "ltfs."