examples: Added required libcurl version information to SMTP examples

docs/examples/smtp-expn.c

@@ -27,7 +27,7 @@
  *
  * Notes:
  *
- * 1) This example requires libcurl v7.34.0 or above.
+ * 1) This example requires libcurl 7.34.0 or above.
  * 2) Not all email servers support this command.
  */
 

docs/examples/smtp-mail.c

@@ -26,6 +26,8 @@
 /* This is a simple example showing how to send mail using libcurl's SMTP
  * capabilities. For an exmaple of using the multi interface please see
  * smtp-multi.c.
+ *
+ * Note that this example requires libcurl 7.20.0 or above.
  */
 
 int main(void)

docs/examples/smtp-multi.c

@@ -19,13 +19,15 @@
  * KIND, either express or implied.
  *
  ***************************************************************************/
-/* This is an example application source code sending SMTP mail using the
- * multi interface.
- */
-
 #include <string.h>
 #include <curl/curl.h>
 
+/* This is an example showing how to send mail using libcurl's SMTP
+ * capabilities via the multi interface.
+ *
+ * Note that this example requires libcurl 7.20.0 or above.
+ */
+
 /*
  * This is the list of basic details you need to tweak to get things right.
  */

docs/examples/smtp-ssl.c

@@ -27,6 +27,8 @@
  * capabilities. It builds on the smtp-mail.c example to add authentication
  * and, more importantly, transport security to protect the authentication
  * details from being snooped.
+ *
+ * Note that this example requires libcurl 7.20.0 or above.
  */
 
 #define FROM    "<sender@example.org>"

docs/examples/smtp-tls.c

@@ -27,6 +27,8 @@
  * capabilities. It builds on the smtp-mail.c example to add authentication
  * and, more importantly, transport security to protect the authentication
  * details from being snooped.
+ *
+ * Note that this example requires libcurl 7.20.0 or above.
  */
 
 #define FROM    "<sender@example.org>"

docs/examples/smtp-vrfy.c

@@ -28,7 +28,7 @@
  *
  * Notes:
  *
- * 1) This example requires libcurl v7.34.0 or above.
+ * 1) This example requires libcurl 7.34.0 or above.
  * 2) Not all email servers support this command and even if your email server
  *    does support it, it may respond with a 252 response code even though the
  *    address doesn't exist.