On compile: linux.c: In function ‘make_mac_path’: linux.c:850:9: error: missing braces around initializer [-Werror=missing-braces] struct ifreq ifr = { 0, };
Can you please attach the full build.log and emerge --info output?
This has been fixed by https://github.com/rhinstaller/efivar/commit/a3606c02fd271d32e364fcc540e34ba1899309f6
+ 19 Jul 2015; Mike Gilbert <floppym@gentoo.org> +files/0.21-initializer.patch, + efivar-0.21.ebuild: + Fix build failure, bug 555384.