tidy-up: miscellaneous

- apply more clang-format.
- lib/version: use `CURL_ARRAYSIZE()`.
- INSTALL-CMAKE.md: sync-up an option description with others.
- examples: delete unused main args.
- examples/ftpgetinfo: document `_CRT_SECURE_NO_WARNINGS` symbol.
- delete remaining stray duplicate lines.
- acinclude.m4: drop an unnecessary x-hack.
- vtls/mbedtls: join a URL split into two lines.
- src/tool_cb_see: add parentheses around macro expressions.
- src/tool_operate: move literals to the right side of comparisons.
- libtests: sync up fopen/fstat error messages between tests.
- curl_setup.h: replace `if ! defined __LP64` with `ifndef __LP64`.
  I assume it makes no difference on Tandem systems, as the latter form
  is already used in `include/curl/system.h`.

Closes #20018

lib/version.c

@@ -551,9 +551,7 @@ static const struct feat features_table[] = {
   {NULL,                 NULL,                0}
 };
 
-static const char *feature_names[sizeof(features_table) /
-                                 sizeof(features_table[0])] = {NULL};
-
+static const char *feature_names[CURL_ARRAYSIZE(features_table)] = { NULL };
 
 static curl_version_info_data version_info = {
   CURLVERSION_NOW,