The hurd buildd got itself lost building petsc 3.7.6. It builds fine on the porterbox. Please give back for building. Once it's done, slepc should be rebuilt against it
gb petsc_3.7.6+dfsg1-2 . hurd-i386 dw slepc_3.7.4+dfsg1-2 . hurd-i386 . -m 'libpetsc3.7.6-dev' nmu slepc_3.7.4+dfsg1-2 . hurd-i386 . -m 'Rebuild against PETSc 3.7.6' Thanks, Drew
