The NetBSD-current/i386 build is working again. The following commits were made between the last failed build and the successful build:
2019.08.15.19.53.01 martin src/usr.sbin/installboot/Makefile,v 1.54 2019.08.15.19.53.01 martin src/usr.sbin/installboot/machines.c,v 1.42 Log files can be found at: http://releng.NetBSD.org/b5reports/i386/commits-2019.08.html#2019.08.15.19.53.01