The NetBSD-current/i386 build is working again. The following commits were made between the last failed build and the successful build:
2016.10.08.23.40.52 joerg src/external/gpl2/groff/dist/src/roff/troff/input.cpp,v 1.4 Log files can be found at: http://releng.NetBSD.org/b5reports/i386/commits-2016.10.html#2016.10.08.23.40.52