Hi,
I need to reference the carp checkout in an environment variable so that
carp can find the libs it needs:
/gnu/store/0xhn0vyjlcb2dv1h2333vhbj7j1vvrr6-carp-0.5.5-checkout
How can I do that?
* carp package definition
```
(define-public carp
(package
(name "carp")
(version "0.5.5")
(source
(origin
(method git-fetch)
(uri (git-reference
(url "https://github.com/carp-lang/Carp";)
(commit (string-append "v" version))))
(file-name (git-file-name name version))
(sha256
(base32 "14jdnv0ljqvpr9ych1plfw7hp5q57a8j1bv8h3v345x06z783d07"))))
(build-system haskell-build-system)
(arguments
`(#:phases
(modify-phases %standard-phases
(add-after 'install 'make-clang-available-at-runtime
(lambda* (#:key inputs outputs #:allow-other-keys)
(let ((out (assoc-ref outputs "out"))
(clang (assoc-ref inputs "clang")))
(wrap-program (string-append out "/bin/carp")
`("CARP_DIR" = (,out))
`("PATH" = (,(string-append clang "/bin"))))
(wrap-program (string-append out "/bin/carp-header-parse")
`("CARP_DIR" = (,out))
`("PATH" = (,(string-append clang "/bin"))))))))))
(native-inputs (list ghc-hunit))
(inputs (list clang
ghc-blaze-markup
ghc-blaze-html
ghc-split
ghc-ansi-terminal
ghc-cmark
ghc-edit-distance
ghc-hashable
ghc-open-browser
ghc-optparse-applicative))
(home-page "https://carp-lang.org/";)
(synopsis "Statically typed Lisp without a garbage collector")
(description
"@code{carp} is a programming language designed to work well for
interactive and performance sensitive use cases like games, sound
synthesis and visualizations.")
(license license:asl2.0)))
```
