Revert r279381. The EFI loader needs to use a separate libstand that

is compiled against the ABI EFI expects (specifically, no stack
redzone) so it cannot share libstand with userboot (which must use
the System V ABI).

sys/boot/amd64/efi/Makefile

@@ -84,7 +84,6 @@ loader.efi: loader.sym
 		--output-target=${EFI_TARGET} ${.ALLSRC} ${.TARGET}
 
 LIBEFI=		${.OBJDIR}/../../efi/libefi/libefi.a
-LIBSTAND=       ${.OBJDIR}/../../userboot/libstand/libstand.a
 
 DPADD=		${LIBFICL} ${LIBEFI} ${LIBSTAND}
 LDADD=		${LIBFICL} ${LIBEFI} ${LIBSTAND}