MINOR: config: Support per-proxy and per-server post-check functions callbacks

Most of times, when a keyword is added in proxy section or on the server line,
we need to have a post-parser callback to check the config validity for the
proxy or the server which uses this keyword.

It is possible to register a global post-parser callback. But all these
callbacks need to loop on the proxies and servers to do their job. It is neither
handy nor efficient. Instead, it is now possible to register per-proxy and
per-server post-check callbacks.
diff --git a/include/types/global.h b/include/types/global.h
index 12f888c..bd08db1 100644
--- a/include/types/global.h
+++ b/include/types/global.h
@@ -288,6 +288,8 @@
 void deinit(void);
 void hap_register_build_opts(const char *str, int must_free);
 void hap_register_post_check(int (*fct)());
+void hap_register_post_proxy_check(int (*fct)(struct proxy *));
+void hap_register_post_server_check(int (*fct)(struct server *));
 void hap_register_post_deinit(void (*fct)());
 void hap_register_proxy_deinit(void (*fct)(struct proxy *));
 void hap_register_server_deinit(void (*fct)(struct server *));
@@ -308,6 +310,14 @@
 #define REGISTER_POST_CHECK(fct) \
 	INITCALL1(STG_REGISTER, hap_register_post_check, (fct))
 
+/* simplified way to declare a post-proxy-check callback in a file */
+#define REGISTER_POST_PROXY_CHECK(fct) \
+	INITCALL1(STG_REGISTER, hap_register_post_proxy_check, (fct))
+
+/* simplified way to declare a post-server-check callback in a file */
+#define REGISTER_POST_SERVER_CHECK(fct) \
+	INITCALL1(STG_REGISTER, hap_register_post_server_check, (fct))
+
 /* simplified way to declare a post-deinit callback in a file */
 #define REGISTER_POST_DEINIT(fct) \
 	INITCALL1(STG_REGISTER, hap_register_post_deinit, (fct))