MINOR: spoe/checks: Add support for SPOP health checks

A new "option spop-check" statement has been added to enable server health
checks based on SPOP HELLO handshake. SPOP is the protocol used by SPOE filters
to talk to servers.
diff --git a/include/proto/checks.h b/include/proto/checks.h
index ecd4a5c..bf771ea 100644
--- a/include/proto/checks.h
+++ b/include/proto/checks.h
@@ -51,6 +51,11 @@
 void send_email_alert(struct server *s, int priority, const char *format, ...)
 	__attribute__ ((format(printf, 3, 4)));
 int srv_check_healthcheck_port(struct check *chk);
+
+/* Declared here, but the definitions are in flt_spoe.c */
+int prepare_spoe_healthcheck_request(char **req, int *len);
+int handle_spoe_healthcheck_response(char *frame, size_t size, char *err, int errlen);
+
 #endif /* _PROTO_CHECKS_H */
 
 /*