#139 pixie-2.2.6 fails with bison-3

[dugz]

Recent upgrades in gentoo stable have caused this bug to resurface. Reference Gentoo Bugzilla Bug 486148 media-gfx/pixie-2.2.6-r1 fails with bison-3 https://bugs.gentoo.org/show_bug.cgi?id=486148 a simple one-line patch is available.