Fixed bug #26847 (memory leak in mail() when to/subject contain only spaces)

ext/standard/mail.c

@@ -160,10 +160,10 @@ PHP_FUNCTION(mail)
 	if (extra_cmd) {
 		efree (extra_cmd);
 	}
-	if (to_len > 0) {
+	if (to_r != to) {
 		efree(to_r);
 	}
-	if (subject_len > 0) {
+	if (subject_r != subject) {
 		efree(subject_r);
 	}
 }