gnu: Add python-cymem

* gnu/packages/python-xyz.scm (python-cymem): New variable.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu/packages/python-xyz.scm

@@ -31640,3 +31640,46 @@ It can generate reports as HTML tables or plain text lists.
 
 Scooby has no required dependencies, and only few optional dependencies.")
     (license license:expat)))
+
+(define-public python-cymem
+  (package
+    (name "python-cymem")
+    (version "2.0.6")
+    (source (origin
+              (method url-fetch)
+              (uri (pypi-uri "cymem" version))
+              (sha256
+               (base32
+                "0pkyy60zk9654sj991w111p1l0m8wvz36nslw96x6nb9h6sjb5qn"))))
+    (build-system python-build-system)
+    (native-inputs
+     (list python-cython
+           python-pytest))
+    (inputs
+     (list python))
+    (arguments
+     (list
+      #:modules '((ice-9 ftw)
+                  (ice-9 match)
+                  (guix build utils)
+                  (guix build python-build-system))
+      #:phases
+      #~(modify-phases %standard-phases
+          (add-after 'unpack 'set-source-file-times-to-1980
+            ;; XXX One of the tests uses a ZIP library to pack up some of the
+            ;; source tree, and fails with "ZIP does not support timestamps
+            ;; before 1980".  Work around this by setting the file times in the
+            ;; source tree to sometime in early 1980.
+            (lambda _
+              (let ((circa-1980 (* 10 366 24 60 60)))
+                (ftw "." (lambda (file stat flag)
+                           (utime file circa-1980 circa-1980)
+                           #t))))))))
+    (home-page "https://github.com/explosion/cymem")
+    (synopsis "Cython memory pool for RAII-style memory management")
+    (description
+     "Cymem provides two small memory-management helpers for Cython.  They make it
+easy to tie memory to a Python object's life-cycle, so that the memory is freed
+when the object is garbage collected.")
+    (license license:expat)))
+