"Optimization flag is not supported" build failure(s) — clang 6.0

PackageVersionSupposed error messageFull log Bug report
libv8-3.14 3.14.5.8-11clang: error: optimization flag '-fno-delete-null-pointer-checks' is not supported [-Werror,-Wignored-optimization-argument] Log
pesign 0.112-4clang: error: optimization flag '-fno-merge-constants' is not supported [-Werror,-Wignored-optimization-argument] Log
pg-cron 1.0.2-1clang: error: optimization flag '-fexcess-precision=standard' is not supported [-Werror,-Wignored-optimization-argument] Log
upx-ucl 3.94-4clang: error: optimization flag '-fno-delete-null-pointer-checks' is not supported [-Werror,-Wignored-optimization-argument] Log

4 errors