unable to expand .apk's

[mcandre]

Unlike .apk's generated directly by Alpine Linux abuild, those generated by fpm struggle to expand on macOS.

The outer gzip archive is able to expand. However, the inner tar archive is not able to expand.

% file hello
hello: POSIX tar archive, file .PKGINFO, mode 0000644, uid 0000000, gid 0000000, size 00000000335, seconds 15141161147
% tar xvf hello
tar: Error opening archive: Unrecognized archive format

Relates to #2131