Hi Javier - back in 2011 (!), you suggested switching to ustar as the default tar format for Automake. Sorry for the absurdly late reply. This has now been done for the upcoming automake-1.18; see discussion in https://debbugs.gnu.org/cgi/bugreport.cgi?bug=74847.
As I guess you know, both then and now, a particular format can be specified with one of the tar-* options (tar-ustar, tar-pax, tar-v7). I'm closing this one now since there's nothing more to do, but feel free to reply/reopen or open a new issue if desired. --thanks, karl.
