examples: fix build issues in 'complicated' examples

- cacertinmem: build cleanly with BoringSSL/AWS-LC.
- cacertinmem: silence `-Wcast-function-type-strict`.
- multi-uv: fix callback prototypes.
- multithread, threaded-ssl: do not pass const as thread arg.
- sessioninfo: fix suppressing deprecated feature warning.
- usercertinmem: sync formatting with cacertinmem.

Follow-up to 4a6bdd5899 #18908
Cherry-picked from #18909
Closes #18914

docs/examples/threaded-ssl.c

@@ -52,12 +52,13 @@ static const char * const urls[]= {
   "https://www4.example.com/",
 };
 
-static void *pull_one_url(void *url)
+static void *pull_one_url(void *pindex)
 {
+  int i = *(int *)pindex;
   CURL *curl;
 
   curl = curl_easy_init();
-  curl_easy_setopt(curl, CURLOPT_URL, url);
+  curl_easy_setopt(curl, CURLOPT_URL, urls[i]);
   /* this example does not verify the server's certificate, which means we
      might be downloading stuff from an impostor */
   curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
@@ -82,7 +83,7 @@ int main(int argc, char **argv)
     int error = pthread_create(&tid[i],
                                NULL, /* default attributes please */
                                pull_one_url,
-                               (void *)urls[i]);
+                               (void *)&i);
     if(error)
       fprintf(stderr, "Couldn't run thread number %d, errno %d\n", i, error);
     else