s-tui: migrate to python3

Includes LC_ALL = "en_US.UTF-8"; that resolves a locale.Error exception
during the check phase.

[...]
  File "/build/s-tui-1.0.0/s_tui/sensors_menu.py", line 27, in <module>
    import urwid
  File "/nix/store/xxhpq1kcjy0kimfwnwqlzh2pchkp9khi-python3.7-urwid-2.1.0/lib/python3.7/site-packages/urwid/__init__.py", line 26, in <module>
    from urwid.widget import (FLOW, BOX, FIXED, LEFT, RIGHT, CENTER, TOP, MIDDLE,
  File "/nix/store/xxhpq1kcjy0kimfwnwqlzh2pchkp9khi-python3.7-urwid-2.1.0/lib/python3.7/site-packages/urwid/widget.py", line 27, in <module>
    from urwid.util import (MetaSuper, decompose_tagmarkup, calc_width,
  File "/nix/store/xxhpq1kcjy0kimfwnwqlzh2pchkp9khi-python3.7-urwid-2.1.0/lib/python3.7/site-packages/urwid/util.py", line 61, in <module>
    detected_encoding = detect_encoding()
  File "/nix/store/xxhpq1kcjy0kimfwnwqlzh2pchkp9khi-python3.7-urwid-2.1.0/lib/python3.7/site-packages/urwid/util.py", line 58, in detect_encoding
    locale.setlocale(locale.LC_ALL, initial)
  File "/nix/store/ja04f3cmapzb3f2mvjrb883bfqclsirq-python3-3.7.6/lib/python3.7/locale.py", line 608, in setlocale
    return _setlocale(category, locale)
locale.Error: unsupported locale setting

1 files changed, 6 insertions, 4 deletions

diff --git a/pkgs/tools/system/s-tui/default.nix b/pkgs/tools/system/s-tui/default.nix
index 924269b6637c..a6816daae33a 100644
--- a/pkgs/tools/system/s-tui/default.nix
+++ b/pkgs/tools/system/s-tui/default.nix
@@ -1,19 +1,21 @@
-{ stdenv, pythonPackages }:
+{ stdenv, python3Packages }:
 
-pythonPackages.buildPythonPackage rec {
+python3Packages.buildPythonPackage rec {
   pname = "s-tui";
   version = "1.0.0";
 
-  src = pythonPackages.fetchPypi {
+  src = python3Packages.fetchPypi {
     inherit pname version;
     sha256 = "0r5yhlsi5xiy7ii1w4kqkaxz9069v5bbfwi3x3xnxhk51yjfgr8n";
   };
 
-  propagatedBuildInputs = with pythonPackages; [
+  propagatedBuildInputs = with python3Packages; [
     urwid
     psutil
   ];
 
+  LC_ALL = "en_US.UTF-8";
+
   meta = with stdenv.lib; {
     homepage = https://amanusk.github.io/s-tui/;
     description = "Stress-Terminal UI monitoring tool";