Add length check, as it turns out the non _ex version returns an empty string rather than NULL in certain cases

Author: Girgias

ext/standard/mail.c

@@ -337,7 +337,7 @@ PHP_FUNCTION(mail)
 	}
 
 	zend_string *force_extra_parameters = zend_ini_str_literal("mail.force_extra_parameters");
-	if (force_extra_parameters) {
+	if (force_extra_parameters && ZSTR_LEN(force_extra_parameters) > 0) {
 		extra_cmd = php_escape_shell_cmd(force_extra_parameters);
 	} else if (extra_cmd) {
 		extra_cmd = php_escape_shell_cmd(extra_cmd);

ext/standard/tests/mail/mail_basic2.phpt

@@ -20,14 +20,17 @@ $message = 'A Message';
 $additional_headers = 'KHeaders';
 $additional_parameters = "-n";
 $outFile = "/tmp/php_test_mailBasic2.out";
-@unlink($outFile);
 
 echo "-- extra parameters --\n";
 // Calling mail() with all possible arguments
 var_dump( mail($to, $subject, $message, $additional_headers, $additional_parameters) );
 
 echo file_get_contents($outFile);
-unlink($outFile);
+
+?>
+--CLEAN--
+<?php
+@unlink("/tmp/php_test_mailBasic2.out");
 ?>
 --EXPECTF--
 *** Testing mail() : basic functionality ***