happy-lib is not happy (content warning: haskell), pandoc broken

[Greg Troxel <gdt%lexort.com@localhost>]

But seriously, on NetBSD 10 amd64, pkgsrc-current, trying to build
happy-lib gets a complaint about wrkdir path in rpath.

objdump -x on the lib shows

  RPATH                /usr/pkg/lib:/usr/pkg/lib/x86_64-netbsd-ghc-9.10.1:/usr/pkg/lib/ghc-9.10.1/lib/x86_64-netbsd-ghc-9.10.1:/tmp/work/devel/happy-lib/work/happy-lib-2.1.6/dist/build/backend-glr:/tmp/work/devel/happy-lib/work/happy-lib-2.1.6/dist/build/frontend

which indeed is not ok.

Does this build for anybody else?

Do we need to have some fixup code to work around upstream not coping
with build/install rpath confusion?