+ HEADER_INCOMPATIBLE_COMPRESSED_XZ = 1 << 0,
+ HEADER_INCOMPATIBLE_COMPRESSED_LZ4 = 1 << 1,
+};
+
+#define HEADER_INCOMPATIBLE_ANY (HEADER_INCOMPATIBLE_COMPRESSED_XZ|HEADER_INCOMPATIBLE_COMPRESSED_LZ4)
+
+#if defined(HAVE_XZ) && defined(HAVE_LZ4)
+# define HEADER_INCOMPATIBLE_SUPPORTED HEADER_INCOMPATIBLE_ANY
+#elif defined(HAVE_XZ)
+# define HEADER_INCOMPATIBLE_SUPPORTED HEADER_INCOMPATIBLE_COMPRESSED_XZ
+#elif defined(HAVE_LZ4)
+# define HEADER_INCOMPATIBLE_SUPPORTED HEADER_INCOMPATIBLE_COMPRESSED_LZ4
+#else
+# define HEADER_INCOMPATIBLE_SUPPORTED 0
+#endif
+
+enum {
+ HEADER_COMPATIBLE_SEALED = 1