+#define SSH_BUG_DERIVEKEY 0x00040000
+#define SSH_BUG_DUMMYCHAN 0x00100000
+#define SSH_BUG_EXTEOF 0x00200000
+#define SSH_BUG_PROBE 0x00400000
+#define SSH_BUG_FIRSTKEX 0x00800000
+#define SSH_OLD_FORWARD_ADDR 0x01000000
+#define SSH_BUG_RFWD_ADDR 0x02000000
+
+void enable_compat13(void);
+void enable_compat20(void);
+void compat_datafellows(const char *);
+int proto_spec(const char *);
+char *compat_cipher_proposal(char *);