The NetBSD-current/i386 build is working again. The following commits were made between the last failed build and the first successful build:
2023.10.27.06.31.48 mrg src/sys/arch/x86/include/specialreg.h 1.209 Logs can be found at: http://releng.NetBSD.org/b5reports/i386/commits-2023.10.html#2023.10.27.06.31.48