tidy-up: miscellaneous

- curl_ntlm_core, smtp, schannel: fix comments.
- curl_setup.h: fix to undef before define.
- tool_doswin, server/sockfilt: reduce variables scopes.
- tool_doswin: drop an interim variable.
- windows: replace `SOCKET_ERROR` with `0` to align with rest of code.
- libssh2: rename variable to align with rest of code.
- gtls, unit1398: use `#if 0`.
- curl_trc.h, curlx/inet_ntop.h: add missing parentheses in macro
  expressions.
- ldap.c: set empty macro to `do {} while(0)`.
- examples/crawler: rename a non-CURLcode `result` variable.
- CURLINFO_TLS_SESSION: drop stray colon.
- add `const` to casts where missing.
- drop unnecessary parentheses.
- fix indent.
- quote style.
- comment style.
- whitespace, newlines, fold/unfold.

Closes #20554

tests/serverhelp.pm

@@ -247,7 +247,7 @@ sub mainsockf_pidfilename {
     my ($piddir, $proto, $ipver, $idnum) = @_;
     die "unsupported protocol: '$proto'" unless($proto &&
         (lc($proto) =~ /^(ftp|imap|pop3|smtp)s?$/));
-    my $trailer = (lc($proto) =~ /^ftps?$/) ? '_sockctrl.pid':'_sockfilt.pid';
+    my $trailer = (lc($proto) =~ /^ftps?$/) ? '_sockctrl.pid' : '_sockfilt.pid';
     return "${piddir}/". servername_canon($proto, $ipver, $idnum) ."$trailer";
 }
 
@@ -258,7 +258,7 @@ sub mainsockf_logfilename {
     my ($logdir, $proto, $ipver, $idnum) = @_;
     die "unsupported protocol: '$proto'" unless($proto &&
         (lc($proto) =~ /^(ftp|imap|pop3|smtp)s?$/));
-    my $trailer = (lc($proto) =~ /^ftps?$/) ? '_sockctrl.log':'_sockfilt.log';
+    my $trailer = (lc($proto) =~ /^ftps?$/) ? '_sockctrl.log' : '_sockfilt.log';
     return "${logdir}/". servername_canon($proto, $ipver, $idnum) ."$trailer";
 }