gnu: python-3.9: Add a search path specification for PYTHONTZPATH.

Python 3.9 implemented PEP 615 (<)https://www.python.org/dev/peps/pep-0615/>),
which relies on either a compiled time default value or the PYTHONTZPATH
environment variable to find the system tzdata database.

* gnu/packages/python.scm (python-3.9)[native-search-paths]: Add a new search
path specification for PYTHONTZPATH.

1 files changed, 6 insertions, 1 deletions

diff --git a/gnu/packages/python.scm b/gnu/packages/python.scm
index 85eb797fd9a..d3df1a4dabe 100644
--- a/gnu/packages/python.scm
+++ b/gnu/packages/python.scm
@@ -475,7 +475,12 @@ data types.")
             (variable "PYTHONPATH")
             (files (list (string-append "lib/python"
                                         (version-major+minor version)
-                                        "/site-packages"))))))))
+                                        "/site-packages"))))
+           ;; Used to locate tzdata by the zoneinfo module introduced in
+           ;; Python 3.9.
+           (search-path-specification
+            (variable "PYTHONTZPATH")
+            (files (list "share/zoneinfo")))))))
 
 ;; Current 3.x version.
 (define-public python-3 python-3.9)