buildPythonPackage: always export LANG=C.UTF-8

doc/languages-frameworks/python.section.md

@@ -881,7 +881,6 @@ example of such a situation is when `py.test` is used.
     '';
   }
   ```
-- Unicode issues can typically be fixed by including `glibcLocales` in `buildInputs` and exporting `LC_ALL=en_US.utf-8`.
 - Tests that attempt to access `$HOME` can be fixed by using the following work-around before running tests (e.g. `preCheck`): `export HOME=$(mktemp -d)`
 
 ## FAQ

nixos/doc/manual/release-notes/rl-1903.xml

@@ -158,12 +158,18 @@
    </listitem>
    <listitem>
     <para>
-      The <varname>buildPythonPackage</varname> now sets <varname>strictDeps = true</varname>
+      The <varname>buildPythonPackage</varname> function now sets <varname>strictDeps = true</varname>
       to help distinguish between native and non-native dependencies in order to
       improve cross-compilation compatibility. Note however that this may break
       user expressions.
     </para>
    </listitem>
+   <listitem>
+    <para>
+      The <varname>buildPythonPackage</varname> function now sets <varname>LANG = C.UTF-8</varname>
+      to enable Unicode support. The <varname>glibcLocales</varname> package is no longer needed as a build input.
+    </para>
+   </listitem>
    <listitem>
     <para>
       The Syncthing state and configuration data has been moved from

pkgs/development/interpreters/python/mk-python-derivation.nix

@@ -90,6 +90,8 @@ let self = toPythonModule (python.stdenv.mkDerivation (builtins.removeAttrs attr
   # Enabled to detect some (native)BuildInputs mistakes
   strictDeps = true;
 
+  LANG = "${if python.stdenv.isDarwin then "en_US" else "C"}.UTF-8";
+
   # Python packages don't have a checkPhase, only an installCheckPhase
   doCheck = false;
   doInstallCheck = doCheck;