flake8: Clean up complained-about unused imports

This also adds a "# noqa: F401" comment on an unused "import lzma",
which we are using it in a try/except block that is being used to
check if the lzma module is importable; of course it is unused.

v2: This turned out to be a little tricky.

    mesonbuild/modules/__init__.py had the "unused" import:

        from ..interpreterbase import permittedKwargs, noKwargs

    However, that meant that the various modules could do things like:

        from . import noKwargs # "." is "mesonbuild.modules"

    Which breaks when you remove __init__.py's "unused" import.  I
    could have tagged that import with "# noqa: F401", but instead I
    chose to have each of the module import directly from
    "..interpreterbase" instead of ".".

mesonbuild/backend/ninjabackend.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import os, pickle, re, shlex, shutil, subprocess, sys
+import os, pickle, re, shlex, subprocess, sys
 from collections import OrderedDict
 
 from . import backends

mesonbuild/backend/vs2010backend.py

@@ -22,7 +22,6 @@
 from .. import dependencies
 from .. import mlog
 from .. import compilers
-from ..build import BuildTarget
 from ..compilers import CompilerArgs
 from ..mesonlib import MesonException, File
 from ..environment import Environment

mesonbuild/modules/__init__.py

@@ -4,7 +4,6 @@
 from .. import dependencies
 from .. import mlog
 from ..mesonlib import MesonException
-from ..interpreterbase import permittedKwargs, noKwargs
 
 class permittedSnippetKwargs:
 

mesonbuild/modules/gnome.py

@@ -17,7 +17,6 @@
 
 from .. import build
 import os
-import sys
 import copy
 import subprocess
 from . import ModuleReturnValue
@@ -30,7 +29,7 @@
 from . import GResourceTarget, GResourceHeaderTarget, GirTarget, TypelibTarget, VapiTarget
 from . import find_program, get_include_args
 from . import ExtensionModule
-from . import noKwargs, permittedKwargs
+from ..interpreterbase import noKwargs, permittedKwargs
 
 # gresource compilation is broken due to the way
 # the resource compiler and Ninja clash about it

mesonbuild/modules/i18n.py

@@ -12,15 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import sys
 import shutil
 
 from os import path
 from .. import coredata, mesonlib, build
 from ..mesonlib import MesonException
 from . import ModuleReturnValue
 from . import ExtensionModule
-from . import permittedKwargs
+from ..interpreterbase import permittedKwargs
 
 PRESET_ARGS = {
     'glib': [

mesonbuild/modules/modtest.py

@@ -14,7 +14,7 @@
 
 from . import ModuleReturnValue
 from . import ExtensionModule
-from . import noKwargs
+from ..interpreterbase import noKwargs
 
 class TestModule(ExtensionModule):
 

mesonbuild/modules/pkgconfig.py

@@ -19,7 +19,7 @@
 from .. import mlog
 from . import ModuleReturnValue
 from . import ExtensionModule
-from . import permittedKwargs
+from ..interpreterbase import permittedKwargs
 
 
 class PkgConfigModule(ExtensionModule):

mesonbuild/modules/python3.py

@@ -18,7 +18,8 @@
 
 from . import ExtensionModule
 from mesonbuild.modules import ModuleReturnValue
-from . import noKwargs, permittedSnippetKwargs
+from . import permittedSnippetKwargs
+from ..interpreterbase import noKwargs
 from ..interpreter import shlib_kwargs
 
 mod_kwargs = set()

mesonbuild/modules/qt4.py

@@ -20,7 +20,7 @@
 from . import ExtensionModule
 import xml.etree.ElementTree as ET
 from . import ModuleReturnValue
-from . import permittedKwargs
+from ..interpreterbase import permittedKwargs
 
 class Qt4Module(ExtensionModule):
     tools_detected = False

mesonbuild/modules/qt5.py

@@ -20,7 +20,7 @@
 from . import ExtensionModule
 import xml.etree.ElementTree as ET
 from . import ModuleReturnValue
-from . import permittedKwargs
+from ..interpreterbase import permittedKwargs
 
 class Qt5Module(ExtensionModule):
     tools_detected = False

mesonbuild/modules/rpm.py

@@ -22,7 +22,7 @@
 from . import GirTarget, TypelibTarget
 from . import ModuleReturnValue
 from . import ExtensionModule
-from . import noKwargs
+from ..interpreterbase import noKwargs
 
 import os
 

mesonbuild/modules/windows.py

@@ -20,7 +20,7 @@
 from . import get_include_args
 from . import ModuleReturnValue
 from . import ExtensionModule
-from . import permittedKwargs
+from ..interpreterbase import permittedKwargs
 
 class WindowsModule(ExtensionModule):
 

mesonbuild/wrap/wrap.py

@@ -299,7 +299,7 @@ def download(self, p, packagename):
     def extract_package(self, package):
         if sys.version_info < (3, 5):
             try:
-                import lzma
+                import lzma # noqa: F401
                 del lzma
             except ImportError:
                 pass

mesonrewriter.py

@@ -23,7 +23,7 @@
 # - move targets
 # - reindent?
 
-from mesonbuild import mesonmain, mlog
+from mesonbuild import mesonmain
 import sys
 
 if __name__ == '__main__':