tidy-up: miscellaneous

- examples: sync debug output printf masks.
- INSTALL-CMAKE.md: tidy up section for some options.
- curl_sha512_256: delete comment suggesting an optimization.
- vtls/keylog: scope a variable.
- vtls/openssl: make a source code URL a permalink.
- vtls/schannel: drop redundant parentheses.
- test1119.pl: robustify `$1` -> `$s`.
- sync arg names in comments to match the code.
- tidy up and minor fixes to comments.
- fix formatting/indenting/comment/newline/include nits.
- move `UNITTEST` protos next to definitions, sync their argument names.
- make variables static.
- add parentheses to Perl `open()` calls.
- drop unnecessary double quotes in Perl.
- clang-format.

Closes #21000

lib/select.c

@@ -274,7 +274,7 @@ int Curl_poll(struct pollfd ufds[], unsigned int nfds, timediff_t timeout_ms)
     if(ufds[i].fd == CURL_SOCKET_BAD)
       continue;
     VERIFY_SOCK(ufds[i].fd);
-    if(ufds[i].events & (POLLIN |POLLOUT |POLLPRI |
+    if(ufds[i].events & (POLLIN | POLLOUT | POLLPRI |
                          POLLRDNORM | POLLWRNORM | POLLRDBAND)) {
       if(ufds[i].fd > maxfd)
         maxfd = ufds[i].fd;
@@ -636,9 +636,9 @@ CURLcode Curl_pollset_set(struct Curl_easy *data,
                           bool do_in, bool do_out)
 {
   return Curl_pollset_change(data, ps, sock,
-                             (do_in ? CURL_POLL_IN : 0)|
+                             (do_in ? CURL_POLL_IN : 0) |
                              (do_out ? CURL_POLL_OUT : 0),
-                             (!do_in ? CURL_POLL_IN : 0)|
+                             (!do_in ? CURL_POLL_IN : 0) |
                              (!do_out ? CURL_POLL_OUT : 0));
 }