gnu: Add cl-weir.

* gnu/packages/lisp-xyz.scm (cl-weir, ecl-weir, sbcl-weir): New variables.

Co-authored-by: Guillaume Le Vaillant <glv@posteo.net>

gnu/packages/lisp-xyz.scm

@@ -16066,3 +16066,54 @@ handling the accessing of files on the underlying system however.")
 
 (define-public cl-pathname-utils
   (sbcl-package->cl-source-package sbcl-pathname-utils))
+
+(define-public sbcl-weir
+  (let ((commit "beb4f6f47f0538d2c6d73b1d3c9d7f58ac8aa0e9")
+        (revision "1"))
+    (package
+      (name "sbcl-weir")
+      (version (git-version "4.9.1" revision commit))
+      (source
+       (origin
+         (method git-fetch)
+         (uri (git-reference
+               (url "https://github.com/inconvergent/weir")
+               (commit commit)))
+         (file-name (git-file-name "weir" version))
+         (sha256
+          (base32 "1vm10kb51g4ba2nl5yixswkk47vwqgwqdlz5031xfff8h9z2a6ad"))))
+      (build-system asdf-build-system/sbcl)
+      (arguments
+       `(#:phases
+         (modify-phases %standard-phases
+           (add-after 'unpack 'fix-tests
+             (lambda _
+               (for-each make-file-writable
+                         (find-files "test/data/")))))))
+      (inputs
+       `(("alexandira" ,sbcl-alexandria)
+         ("cl-json" ,sbcl-cl-json)
+         ("cl-svg" ,sbcl-cl-svg)
+         ("inferior-shell" ,sbcl-inferior-shell)
+         ("lparallel" ,sbcl-lparallel)
+         ("png" ,sbcl-png)
+         ("split-sequence" ,sbcl-split-sequence)
+         ("zpng" ,sbcl-zpng)))
+      (home-page "https://github.com/inconvergent/weir")
+      (synopsis "System for making generative systems")
+      (description
+       "This package provides a Common Lisp system for generating 2d and 3d
+vector artworks with SVG and PNG export format.")
+      (license license:expat))))
+
+(define-public ecl-weir
+  (let ((pkg (sbcl-package->ecl-package sbcl-weir)))
+    (package
+      (inherit pkg)
+      (arguments
+       (substitute-keyword-arguments (package-arguments pkg)
+         ;; FIXME: 17 tests out of 128 are failing on ECL.
+         ((#:tests? _ #f) #f))))))
+
+(define-public cl-weir
+  (sbcl-package->cl-source-package sbcl-weir))