Skip ppm.t in Module::Build if running under PERL_CORE.
From #p5p
[17:54] <@Steffen> avar, is blead passing the M::B ppm.t test again?
[17:54] <@Steffen> Asking because of the release.
[17:55] * avar checks
<snip>
[18:19] <@avar> xdg: zomg plz fix it wtf bbq
[18:19] <@avar> :)
<snip>
[19:07] <@xdg> avar, nopaste the failure and I'll look at it tonight. Worst case, just rm ppm.t --
it's not critical and it's a finicky test. (Passes for me.)
[19:07] * xdg nap &
[19:09] <@avar> willdo later when I get home, unless someone beats me to it *hint*