Fix windows build

.github/workflows/python-app.yml

@@ -65,6 +65,17 @@ jobs:
       #     # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
       #     flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
       - name: Build libmixin.a
+        if: ${{ matrix.os == 'windows-2019' }}
+        working-directory: src/mixin
+        shell: cmd
+        run: |
+          choco install visualstudio2019buildtools --package-parameters "--add Microsoft.VisualStudio.Component.VC.Tools.x86.x64"
+          go build -o mixin.dll -buildmode=c-shared
+          copy mixin.dll ../../pysrc/mixin.dll
+          gendef mixin.dll
+          cmd /c "`"C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\VC\Auxiliary\Build\vcvars64.bat`" && lib /def:mixin.def /machine:x64 /out:mixin.lib"
+      - name: Build libmixin.a
+        if: ${{ matrix.os != 'windows-2019' }}
         working-directory: src/mixin
         run: |
           go build -o libmixin.a -buildmode=c-archive

setup.py

@@ -28,31 +28,6 @@
 
 dir_name = os.path.dirname(os.path.realpath(__file__))
 
-root_path = os.path.join(dir_name, 'src/mixin')
-def check_modification():   
-    lib_name = os.path.join(root_path, 'libmixin.a')
-    if not os.path.exists(lib_name):
-        return True
-    modify_time = os.path.getmtime(lib_name)
-    for root, dirs, files in os.walk(root_path):
-        for f in files:
-            if f[-3:] == '.go':
-                f = os.path.join(root, f)
-                file_time = os.path.getmtime(f)
-                if modify_time < file_time:
-                    return True
-    return False
-
-r = check_modification()
-if r:
-    print('mixin lib need to rebuild.')
-    os.system(f'touch {root_path}/main.go')
-
-if platform.system() == 'Windows':
-    os.system('cd ./src/mixin &&go build -o mixin.dll -buildmode=c-shared && copy mixin.dll ../../pysrc/mixin.dll && gendef mixin.dll && lib /def:mixin.def /machine:x64 /out:mixin.lib')
-else:
-    os.system('cd ./src/mixin;go build -o libmixin.a -buildmode=c-archive')
-
 ext_modules = [
     Extension(
         'pymixin._mixin',