"-Wvarargs: undefined behavior with va_start" build failure(s) — clang 3.9.1

PackageVersionSupposed error messageFull log Bug report
binutils-avr 2.26.20160125+Atmel3.5.4-1bfd.c:511:21: error: passing an object that undergoes default argument promotion to 'va_start' has undefined behavior [-Werror,-Wvarargs] Log
binutils-msp430 2.22~msp20120406-5.1bfd.c:470:21: error: passing an object that undergoes default argument promotion to 'va_start' has undefined behavior [-Werror,-Wvarargs] Log
geis 2.2.17-1.1geis_filter.c:483:21: error: passing an object that undergoes default argument promotion to 'va_start' has undefined behavior [-Werror,-Wvarargs] Log 751539
ion 3.2.1+dfsg-1.1bp/utils/cgrfetch.c:364:17: error: passing an object that undergoes default argument promotion to 'va_start' has undefined behavior [-Werror,-Wvarargs] Log 754319
kore 2.0.0-2src/pgsql.c:222:17: error: passing an object that undergoes default argument promotion to 'va_start' has undefined behavior [-Werror,-Wvarargs] Log
libisds 0.10.6-1isds.c:1142:18: error: passing an object that undergoes default argument promotion to 'va_start' has undefined behavior [-Werror,-Wvarargs] Log

6 errors