"-Wvarargs: undefined behavior with va_start" build failure(s) — clang 8.0.1

PackageVersionSupposed error messageFull log Bug report
fuzzylite 6.0+dfsg-2Operation.h:1044:24: error: passing an object that undergoes default argument promotion to 'va_start' has undefined behavior [-Werror,-Wvarargs] Log
libisds 0.10.7-1isds.c:1142:18: error: passing an object that undergoes default argument promotion to 'va_start' has undefined behavior [-Werror,-Wvarargs] Log

2 errors