Use a custom init function for samba4 that sets a samba4

specific debug function.
By default do not debug, this is the most appropriate action for a library
as we cannot assume what stderr is use for in the main app.
The main app is responsible to set ev_debug_stderr if they so desire.
(This used to be commit e566a2f308)

source4/utils/net/net.c

@@ -185,7 +185,7 @@ static int binary_net(int argc, const char **argv)
 
 	dcerpc_init();
 
-	ev = event_context_init(NULL);
+	ev = s4_event_context_init(NULL);
 	if (!ev) {
 		d_printf("Failed to create an event context\n");
 		exit(1);

source4/utils/nmblookup.c

@@ -359,7 +359,7 @@ int main(int argc, const char *argv[])
 
 	load_interfaces(NULL, lp_interfaces(cmdline_lp_ctx), &ifaces);
 
-	ev = event_context_init(talloc_autofree_context());
+	ev = s4_event_context_init(talloc_autofree_context());
 
 	while (poptPeekArg(pc)) {
 		const char *name = poptGetArg(pc);

source4/utils/ntlm_auth.c

@@ -462,7 +462,7 @@ static void manage_gensec_request(enum stdio_helper_mode stdio_helper_mode,
 		return;
 	}
 
-	ev = event_context_init(state);
+	ev = s4_event_context_init(state);
 	if (!ev) {
 		exit(1);
 	}