The NetBSD-current/i386 build is working again. The following commits were made between the last failed build and the successful build:
2018.10.11.18.04.06 christos src/etc/mtree/NetBSD.dist.base,v 1.179 Log files can be found at: http://releng.NetBSD.org/b5reports/i386/commits-2018.10.html#2018.10.11.18.04.06