Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

[PowerPC64LE] Add release building script for powerpc64le.

This was originally part of the initial commit, but after discussion in
D26399, I split it out into its own commit after the kernel config file.

Sponsored by: Tag1 Consulting, Inc.