Ensure SEEK_SET is set on systems where stdio.h is not pulled in by accident.

src/lib/cdio/Paranoia.hxx

@@ -43,6 +43,8 @@
 #include <stdexcept>
 #include <utility>
 
+#include <cstdio>
+
 class CdromDrive {
 	cdrom_drive_t *drv = nullptr;