Remove $FreeBSD$: one-line .c comment pattern

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

libnetbsd: add emalloc and friends

These are error-checked versions of memory allocation routines used by
NetBSD code, and are being added to facilitate updates to makefs.

Reviewed by: ngie
Differential Revision: https://reviews.freebsd.org/D10291