CURLOPT: drop redundant long casts

Also:
- CURLOPT_HSTS_CTRL.md: sync macro definitions with `curl/curl.h`.
  Perhaps it'd be better to delete copies like this?
- keep existing casts within the documentation to make sure it applies
  to older curl versions as well.
- CURLOPT_IPRESOLVE.md: re-add a long cast to man page, for consistency
  with the above.

Closes #17791

docs/examples/anyauthput.c

@@ -142,7 +142,7 @@ int main(int argc, char **argv)
     /* tell libcurl we can use "any" auth, which lets the lib pick one, but it
        also costs one extra round-trip and possibly sending of all the PUT
        data twice!!! */
-    curl_easy_setopt(curl, CURLOPT_HTTPAUTH, (long)CURLAUTH_ANY);
+    curl_easy_setopt(curl, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
 
     /* set user name and password for the authentication */
     curl_easy_setopt(curl, CURLOPT_USERPWD, "user:password");

docs/examples/ghiper.c

@@ -66,7 +66,7 @@
 #include <curl/curl.h>
 
 #define MSG_OUT g_print   /* Change to "g_error" to write to stderr */
-#define SHOW_VERBOSE 0    /* Set to non-zero for libcurl messages */
+#define SHOW_VERBOSE 0L   /* Set to non-zero for libcurl messages */
 #define SHOW_PROGRESS 0   /* Set to non-zero to enable progress callback */
 
 /* Global information, common to all connections */
@@ -311,7 +311,7 @@ static void new_conn(const char *url, struct GlobalInfo *g)
   curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url);
   curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb);
   curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, &conn);
-  curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, (long)SHOW_VERBOSE);
+  curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, SHOW_VERBOSE);
   curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error);
   curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn);
   curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, SHOW_PROGRESS ? 0L : 1L);

docs/examples/hsts-preload.c

@@ -87,7 +87,7 @@ int main(void)
     struct state st = {0};
 
     /* enable HSTS for this handle */
-    curl_easy_setopt(curl, CURLOPT_HSTS_CTRL, (long)CURLHSTS_ENABLE);
+    curl_easy_setopt(curl, CURLOPT_HSTS_CTRL, CURLHSTS_ENABLE);
 
     /* function to call at first to populate the cache before the transfer */
     curl_easy_setopt(curl, CURLOPT_HSTSREADFUNCTION, hstsread);

docs/examples/http3.c

@@ -38,8 +38,7 @@ int main(void)
     curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
 
     /* Use HTTP/3 but fallback to earlier HTTP if necessary */
-    curl_easy_setopt(curl, CURLOPT_HTTP_VERSION,
-                     (long)CURL_HTTP_VERSION_3);
+    curl_easy_setopt(curl, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_3);
 
     /* Perform the request, res gets the return code */
     res = curl_easy_perform(curl);

docs/examples/imap-tls.c

@@ -57,7 +57,7 @@ int main(void)
      * of using CURLUSESSL_TRY here, because if TLS upgrade fails, the
      * transfer continues anyway - see the security discussion in the libcurl
      * tutorial for more details. */
-    curl_easy_setopt(curl, CURLOPT_USE_SSL, (long)CURLUSESSL_ALL);
+    curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_ALL);
 
     /* If your server does not have a valid certificate, then you can disable
      * part of the Transport Layer Security protection by setting the

docs/examples/pop3-tls.c

@@ -56,7 +56,7 @@ int main(void)
      * using CURLUSESSL_TRY here, because if TLS upgrade fails, the transfer
      * continues anyway - see the security discussion in the libcurl tutorial
      * for more details. */
-    curl_easy_setopt(curl, CURLOPT_USE_SSL, (long)CURLUSESSL_ALL);
+    curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_ALL);
 
     /* If your server does not have a valid certificate, then you can disable
      * part of the Transport Layer Security protection by setting the

docs/examples/smtp-tls.c

@@ -110,7 +110,7 @@ int main(void)
      * of using CURLUSESSL_TRY here, because if TLS upgrade fails, the
      * transfer continues anyway - see the security discussion in the libcurl
      * tutorial for more details. */
-    curl_easy_setopt(curl, CURLOPT_USE_SSL, (long)CURLUSESSL_ALL);
+    curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_ALL);
 
     /* If your server does not have a valid certificate, then you can disable
      * part of the Transport Layer Security protection by setting the