The NetBSD-current/i386 build is working again. The following commits were made between the last failed build and the successful build:
2019.08.10.15.02.03 kamil src/sys/sys/event.h,v 1.35 Log files can be found at: http://releng.NetBSD.org/b5reports/i386/commits-2019.08.html#2019.08.10.15.02.03