audio/vgmplay: correct endianness on big-endian architectures

By default little-endian is specified, which may result in runtime issues. Set it to big-endian where needed.

Also add USES=localbase:ldflags.

PR: 237173
Approved by: tagattie@yandex.com (maintainer), linimon (mentor)
Differential Revision: https://reviews.freebsd.org/D19994