Implicit function error - Rebuild of the Debian archive with clang

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

Versions: 2.9 - 3.0 - 3.1 - 3.2 - 3.3 - 3.4 - 3.4.2 - 3.5.0 - 3.6.0 - 3.8.1 - 3.9.1 - 4.0.1 - 5.0 - 6.0 - 8.0.1 - 9.0.1 - 10.0.0 - 11.0.0 - 12.0.1 - 13.0.0

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

2 errors

Debian Package rebuild