The NetBSD-current/i386 build is working again. The following commits were made between the last failed build and the successful build:
2018.06.17.01.07.06 thorpej src/sys/dev/i2c/am2315.c,v 1.4 2018.06.17.01.08.15 thorpej src/sys/dev/i2c/am2315.c,v 1.5 Log files can be found at: http://releng.NetBSD.org/b5reports/i386/commits-2018.06.html#2018.06.17.01.08.15