BUILD: http_rules: do not declare http_*_keywords_registre() inline

The 3 functions http_{req,res,after_res}_keywords_register() are
referenced in initcalls by their pointer, it makes no sense to declare
them inline. At best it causes function duplication, at worst it doesn't
build on older compilers.
diff --git a/include/haproxy/http_rules.h b/include/haproxy/http_rules.h
index 060e3e8..1820bbd 100644
--- a/include/haproxy/http_rules.h
+++ b/include/haproxy/http_rules.h
@@ -37,20 +37,9 @@
 struct redirect_rule *http_parse_redirect_rule(const char *file, int linenum, struct proxy *curproxy,
                                                const char **args, char **errmsg, int use_fmt, int dir);
 
-static inline void http_req_keywords_register(struct action_kw_list *kw_list)
-{
-	LIST_APPEND(&http_req_keywords.list, &kw_list->list);
-}
-
-static inline void http_res_keywords_register(struct action_kw_list *kw_list)
-{
-	LIST_APPEND(&http_res_keywords.list, &kw_list->list);
-}
-
-static inline void http_after_res_keywords_register(struct action_kw_list *kw_list)
-{
-	LIST_APPEND(&http_after_res_keywords.list, &kw_list->list);
-}
+void http_req_keywords_register(struct action_kw_list *kw_list);
+void http_res_keywords_register(struct action_kw_list *kw_list);
+void http_after_res_keywords_register(struct action_kw_list *kw_list);
 
 struct action_kw *action_http_req_custom(const char *kw);
 struct action_kw *action_http_res_custom(const char *kw);
diff --git a/src/http_rules.c b/src/http_rules.c
index 0d6e165..2ed9dfc 100644
--- a/src/http_rules.c
+++ b/src/http_rules.c
@@ -50,6 +50,21 @@
        .list = LIST_HEAD_INIT(http_after_res_keywords.list)
 };
 
+void http_req_keywords_register(struct action_kw_list *kw_list)
+{
+	LIST_APPEND(&http_req_keywords.list, &kw_list->list);
+}
+
+void http_res_keywords_register(struct action_kw_list *kw_list)
+{
+	LIST_APPEND(&http_res_keywords.list, &kw_list->list);
+}
+
+void http_after_res_keywords_register(struct action_kw_list *kw_list)
+{
+	LIST_APPEND(&http_after_res_keywords.list, &kw_list->list);
+}
+
 /*
  * Return the struct http_req_action_kw associated to a keyword.
  */