Hi ng0,

> and the Cargo.lock of libc is long. My assumption was it has no
> real dependencies. 0. Nada. Nichts.
> 
> I think I have to read more into rust packaging, in the meantime
> it would be good if someone with reference to the first email and
> the email I referenced in there could reply about their knowledge
> of the rust/cargo build system. I'm okay with stabbing in the
> dark, but shared expertise is good.

The rust-build-system takes a wild guess as to what is a library and
what isn't.  The Cargo.lock "freezes" the dependencies to a known-good
configuration - and most libraries don't do that.  So the rust-build-system
uses that as a clue - if there's a file named "Cargo.lock" then the thing
is treated as a program (which means that the build system will invoke
"cargo install" on it).

My rust-libc package definition is:

(define-public rust-libc
  (package
    (name "rust-libc")
    (version "0.2.18")
    (source
     (origin
       (method url-fetch)
       ;; (crate-uri "libc" version) doesn't contain libc-test.
       (uri (string-append "https://github.com/rust-lang/libc/archive/" version ".tar.gz"))
       (file-name (string-append name "-" version ".tar.gz"))
       (sha256
        (base32
         "1mh62gfm91aypbr830m2qklwgscgb0pcfpxzi3a6k60faamlrndf"))))
    (build-system cargo-build-system)
    ;(native-inputs
    ; `(("rust-ctest-bootstrap" ,rust-ctest-bootstrap "src")))
    (arguments
     `(#:tests? #f ; missing dependencies
       #:phases
       (modify-phases %standard-phases
         (add-after 'unpack 'delete-lock
           (lambda _
             (delete-file "Cargo.lock")
             #t))
         (delete 'build))))
    (home-page "https://github.com/rust-lang/libc")
    (synopsis "Raw bindings to platform APIs for Rust")
    (description
     "Libc provides a library for types and bindings to native
C functions often found in libc or other common platform libraries.")
    ;; Choose either license.
    (license (list license:expat license:asl2.0))))

I've attached the other crates I have (most of them unfinished).

The main problems is dependency cycles, as usual.