Log Message:
audio/spiralloops: Fix iostream / Fix DragonFly / amd64

Replace <iostream.h> and <fstream.h> with their c++ counterparts.
Addition of <string.h> was originally under a DragonFly macro, but
this was removed when it was shown NetBSD 5.99 x86_64 needed it too.
Allow package to build on all x86_64 architectures.