I downloaded latest 7.6 stable source (7.6.132) and used debian stuff included (directory packaging/debian).
Ah. That directory is unmaintained. You can try using the packaging from Squeeze or the debian directory from svn://anonscm.debian.org/pkg-pike/branches/7.6-stable/ but with the nettle-2.1.patch from svn://anonscm.debian.org/pkg-pike/branches/7.8-stable/ instead, actually.