Fix #10886: Use more robust method of determining php-cgi

Use the php_sapi_name function to check if the script is being executed
from the command line. This is more robust than checking if the server
port variable is defined by PHP.

Thanks to ha17 for this suggestion.

scripts/checkin.php

@@ -22,8 +22,7 @@
 require_once( dirname( dirname( __FILE__ ) ) . DIRECTORY_SEPARATOR . 'core.php' );
 
 # Make sure this script doesn't run via the webserver
-/** @todo This is a hack to detect php-cgi, there must be a better way. */
-if( isset( $_SERVER['SERVER_PORT'] ) ) {
+if( php_sapi_name() != 'cli' ) {
 	echo "checkin.php is not allowed to run through the webserver.\n";
 	exit( 1 );
 }

scripts/send_emails.php

@@ -25,8 +25,7 @@
 require_once( 'email_api.php' );
 
 # Make sure this script doesn't run via the webserver
-/** @todo This is a hack to detect php-cgi, there must be a better way. */
-if( isset( $_SERVER['SERVER_PORT'] ) ) {
+if( php_sapi_name() != 'cli' ) {
 	echo "send_emails.php is not allowed to run through the webserver.\n";
 	exit( 1 );
 }