MEDIUM: init: convert all trivial registration calls to initcalls

This switches explicit calls to various trivial registration methods for
keywords, muxes or protocols from constructors to INITCALL1 at stage
STG_REGISTER. All these calls have in common to consume a single pointer
and return void. Doing this removes 26 constructors. The following calls
were addressed :

- acl_register_keywords
- bind_register_keywords
- cfg_register_keywords
- cli_register_kw
- flt_register_keywords
- http_req_keywords_register
- http_res_keywords_register
- protocol_register
- register_mux_proto
- sample_register_convs
- sample_register_fetches
- srv_register_keywords
- tcp_req_conn_keywords_register
- tcp_req_cont_keywords_register
- tcp_req_sess_keywords_register
- tcp_res_cont_keywords_register
- flt_register_keywords
diff --git a/src/memory.c b/src/memory.c
index 17ac1d1..1554243 100644
--- a/src/memory.c
+++ b/src/memory.c
@@ -18,6 +18,7 @@
 #include <common/config.h>
 #include <common/debug.h>
 #include <common/hathreads.h>
+#include <common/initcall.h>
 #include <common/memory.h>
 #include <common/mini-clist.h>
 #include <common/standard.h>
@@ -526,11 +527,7 @@
 	{{},}
 }};
 
-__attribute__((constructor))
-static void __memory_init(void)
-{
-	cli_register_kw(&cli_kws);
-}
+INITCALL1(STG_REGISTER, cli_register_kw, &cli_kws);
 
 /*
  * Local variables: