gnu: chez-scheme: Explicitly package bootstrap bootfiles.

This makes the structure of the upstream Chez Scheme package the same as
for the Racket variant, it sets things up for (one day, hopefully)
actually being able to bootstrap the upstream Chez Scheme bootfiles, and
it may be useful for cross-compilation and adding support for
architectures without pre-built bootfiles from upstream.

* gnu/packages/chez.scm (chez-scheme-bootstrap-bootfiles): New
variable.
(chez-scheme)[native-inputs]: Add it.
[arguments]<#:phases>: Add 'unpack-bootfiles'.
(chez-scheme-for-racket-bootstrap-bootfiles): Inherit from
'chez-scheme-bootstrap-bootfiles'.
[arguments]: Adapt accordingly.

Signed-off-by: Liliana Marie Prikler <liliana.prikler@gmail.com>

gnu/packages/chez.scm

@@ -46,6 +46,7 @@ (define-module (gnu packages chez)
   #:use-module (gnu packages xorg)
   #:use-module (ice-9 match)
   #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-26)
   #:export (nix-system->chez-machine
             chez-machine->nonthreaded
             chez-machine->threaded
@@ -211,7 +212,9 @@ (define-public chez-scheme
       ;; for X11 clipboard support in expeditor:
       ;; https://github.com/cisco/ChezScheme/issues/9#issuecomment-222057232
       libx11))
-    (native-inputs (list chez-nanopass-bootstrap stex-bootstrap))
+    (native-inputs (list chez-scheme-bootstrap-bootfiles
+                         chez-nanopass-bootstrap
+                         stex-bootstrap))
     (native-search-paths
      (list (search-path-specification
             (variable "CHEZSCHEMELIBDIRS")
@@ -232,6 +235,14 @@ (define-public chez-scheme
           (add-after 'unpack 'unpack-nanopass+stex
             (lambda args
               #$unpack-nanopass+stex))
+          (add-after 'unpack-nanopass+stex 'unpack-bootfiles
+            (lambda* (#:key native-inputs inputs #:allow-other-keys)
+              (when (directory-exists? "boot")
+                (delete-file-recursively "boot"))
+              (copy-recursively
+               (search-input-directory (or native-inputs inputs)
+                                       "lib/chez-scheme-bootfiles")
+               "boot")))
           ;; NOTE: the custom Chez 'configure' script doesn't allow
           ;; unrecognized flags, such as those automatically added
           ;; by `gnu-build-system`.
@@ -316,8 +327,46 @@ (define* (stex-make #:optional (suffix ""))
 and 32-bit PowerPC architectures.")
     (license asl2.0)))
 
+(define-public chez-scheme-bootstrap-bootfiles
+  (package
+    (inherit chez-scheme)
+    (name "chez-scheme-bootstrap-bootfiles")
+    (inputs '())
+    (native-inputs '())
+    (outputs '("out"))
+    (build-system copy-build-system)
+    ;; TODO: cross compilation
+    (arguments
+     (list #:install-plan
+           #~`(("boot/" "lib/chez-scheme-bootfiles"))))
+    (supported-systems
+     ;; Upstream only distributes pre-built bootfiles for
+     ;; arm32le and t?(i3|a6)(le|nt|osx)
+     (filter (lambda (system)
+               (let ((machine (and=> (nix-system->chez-machine system)
+                                     chez-machine->nonthreaded)))
+                 (or (equal? "arm32le" machine)
+                     (and machine
+                          (member (substring machine 0 2) '("i3" "a6"))
+                          (or-map (cut string-suffix? <> machine)
+                                  '("le" "nt" "osx"))))))
+             %supported-systems))
+    (synopsis "Chez Scheme bootfiles (binary seed)")
+    (description
+     "Chez Scheme is a self-hosting compiler: building it requires
+``bootfiles'' containing the Scheme-implemented portions compiled for the
+current platform.  (Chez can then cross-compile bootfiles for all other
+supported platforms.)
+
+This package provides bootstrap bootfiles for upstream Chez Scheme.
+Currently, it simply packages the binaries checked in to the upsream
+repository.  Hopefully we can eventually adapt Racket's @code{cs-bootstrap} to
+work with upstream Chez Scheme so that we can bootstrap these files from
+source.")))
+
 (define-public chez-scheme-for-racket-bootstrap-bootfiles
   (package
+    (inherit chez-scheme-bootstrap-bootfiles)
     (name "chez-scheme-for-racket-bootstrap-bootfiles")
     (version "9.5.7.3")
     ;; The version should match `(scheme-fork-version-number)`.
@@ -325,17 +374,15 @@ (define-public chez-scheme-for-racket-bootstrap-bootfiles
     ;; It will always be different than the upstream version!
     ;; When updating, remember to also update %racket-version in racket.scm.
     (source #f) ; avoid problematic cycle with racket.scm
-    (inputs `())
     (native-inputs (list chez-nanopass-bootstrap racket-vm-bc))
-    (build-system copy-build-system)
     ;; TODO: cross compilation
     (arguments
-     (list
-      #:install-plan
-      #~`(("boot/" "lib/chez-scheme-bootfiles"))
-      #:phases
-      #~(let ((unpack (assoc-ref %standard-phases 'unpack)))
-          (modify-phases %standard-phases
+     (substitute-keyword-arguments
+         (package-arguments chez-scheme-bootstrap-bootfiles)
+       ((#:phases those-phases #~%standard-phases)
+        #~(let* ((those-phases #$those-phases)
+                 (unpack (assoc-ref those-phases 'unpack)))
+            (modify-phases those-phases
               (replace 'unpack
                 (lambda args
                   (unpack #:source #$(or (package-source this-package)
@@ -350,7 +397,7 @@ (define-public chez-scheme-for-racket-bootstrap-bootfiles
                 (lambda* (#:key native-inputs inputs #:allow-other-keys)
                   (invoke (search-input-file (or native-inputs inputs)
                                              "/opt/racket-vm/bin/racket")
-                        "rktboot/main.rkt")))))))
+                          "rktboot/main.rkt"))))))))
     (supported-systems (filter nix-system->chez-machine
                                %supported-systems))
     (home-page "https://github.com/racket/ChezScheme")
@@ -372,8 +419,7 @@ (define-public chez-scheme-for-racket-bootstrap-bootfiles
 
 Note that the generated bootfiles are specific to Racket's fork of Chez
 Scheme, and @code{cs-bootstrap} does not currently support building upstream
-Chez Scheme.")
-    (license (list asl2.0))))
+Chez Scheme.")))
 
 ;;
 ;; Chez's bootstrap dependencies: