Fix flake8 'imported but unused' reports

$ flake8 | grep F401
./meson.py:17:1: F401 'mesonbuild.mesonlib' imported but unused
./meson.py:18:1: F401 'locale' imported but unused
./run_unittests.py:24:1: F401 'sys' imported but unused
./mesonbuild/minit.py:2:1: F401 'pyclbr.Function' imported but unused
./mesonbuild/minit.py:18:1: F401 'os' imported but unused
./mesonbuild/backend/vs2010backend.py:15:1: F401 'sys' imported but unused
./mesonbuild/backend/xcodebackend.py:19:1: F401 'sys' imported but unused
./mesonbuild/dependencies/ui.py:20:1: F401 'shutil' imported but unused
./mesonbuild/modules/python3.py:15:1: F401 'sys' imported but unused
./mesonbuild/modules/unstable_icestorm.py:15:1: F401 '..compilers' imported but unused
./mesonbuild/modules/unstable_icestorm.py:15:1: F401 '..mlog' imported but unused
./test cases/common/98 gen extra/srcgen3.py:3:1: F401 'os' imported but unused

meson.py

@@ -14,8 +14,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from mesonbuild import mesonmain, mesonlib
-import sys, os, locale
+from mesonbuild import mesonmain
+import sys, os
 
 def main():
     # Always resolve the command path so Ninja can find it for regen, tests, etc.

mesonbuild/backend/vs2010backend.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import os, sys
+import os
 import pickle
 import xml.dom.minidom
 import xml.etree.ElementTree as ET

mesonbuild/backend/xcodebackend.py

@@ -16,7 +16,7 @@ from . import backends
 from .. import build
 from .. import dependencies
 from .. import mesonlib
-import uuid, os, sys
+import uuid, os
 
 from ..mesonlib import MesonException
 

mesonbuild/dependencies/ui.py

@@ -17,7 +17,6 @@
 
 import os
 import re
-import shutil
 import subprocess
 from collections import OrderedDict
 

mesonbuild/minit.py

@@ -1,5 +1,4 @@
 # Copyright 2017 The Meson development team
-from pyclbr import Function
 
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -15,7 +14,7 @@ from pyclbr import Function
 
 """Code that creates simple startup projects."""
 
-import os, sys, argparse, re
+import sys, argparse, re
 from glob import glob
 
 lib_h_template = '''#pragma once

mesonbuild/modules/python3.py

@@ -12,7 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import sys
 import sysconfig
 from .. import mesonlib, dependencies
 

mesonbuild/modules/unstable_icestorm.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from .. import mesonlib, compilers, mlog
+from .. import mesonlib
 
 from . import ExtensionModule
 

run_unittests.py

@@ -21,7 +21,6 @@ import tempfile
 import textwrap
 import os
 import shutil
-import sys
 import unittest
 from unittest import mock
 from configparser import ConfigParser

test cases/common/98 gen extra/srcgen3.py

@@ -1,6 +1,5 @@
 #!/usr/bin/env python3
 
-import os
 import sys
 import argparse