"Implicit function error" build failure(s) — clang 3.8.1

PackageVersionSupposed error messageFull log Bug report
efivar 0.23-2efivar.h:92:6: error: use of unknown builtin '__builtin_va_arg_pack_len' [-Wimplicit-function-declaration] Log
smpq 1.5-1main.c:510:65: error: implicit declaration of function 'strcasecmp' [-Werror,-Wimplicit-function-declaration] Log

2 errors