View on pledge promise dynamic string creation

Hi,

I was wondering what are the views on having the pledge(2) promise 
assembled (in a 3rd party app). Scanning through base and ports, I could 
only find pledge(2) promises as constant string argument. I did assume 
that it's the safest way to make sure that the promise can't be fiddled 
with.

Since the app (Chrony) was not designed with pledge in mind, if became 
more readable to assemble the promise string like:

(https://gitlab.com/chrony/chrony/-/commit/0ea7607358cc)
--- upstream commit 0ea76073 ---

   if (snprintf(promises, sizeof (promises), "stdio%s%s%s%s",
                needs_main_misc ? " rpath wpath cpath inet unix dns" : "",
                needs_recvfd ? " recvfd" : "",
                needs_sendfd ? " sendfd" : "",
                needs_settime ? " settime" : "") >= sizeof (promises))
     assert(0);

   DEBUG_LOG("Pledging: %s", promises);

   if (pledge(promises, NULL) < 0)
     LOG_FATAL("pledge() failed");

---

Originally I stuck to the constant strings and Miroslav optimized it 
after another change would have resulted in more complex if/else constructs.