gh-111062 Set up free-threaded CI for windows

Author: corona10

.github/workflows/build.yml

@@ -179,10 +179,19 @@ jobs:
         run: make check-c-globals
 
   build_win:
+    name: 'Windows'
     needs: check_source
     if: needs.check_source.outputs.run_tests == 'true'
     uses: ./.github/workflows/reusable-build-win.yml
 
+  build_win_free_threaded:
+    name: 'Windows (free-threaded)'
+    needs: check_source
+    if: needs.check_source.outputs.run_tests == 'true' && contains(github.event.pull_request.labels.*.name, 'topic-free-threaded')
+    uses: ./.github/workflows/reusable-build-win.yml
+    with:
+      free-threaded: true
+
   build_macos:
     name: 'macOS'
     needs: check_source

.github/workflows/reusable-build-win.yml

@@ -1,9 +1,14 @@
 on:
   workflow_call:
+    inputs:
+      free-threaded:
+        required: false
+        type: boolean
+        default: false
 
 jobs:
   build_win_32:
-    name: 'Windows (x86)'
+    name: 'x86'
     runs-on: windows-latest
     timeout-minutes: 60
     env:
@@ -15,10 +20,10 @@ jobs:
     - name: Display build info
       run: .\python.bat -m test.pythoninfo
     - name: Tests
-      run: .\PCbuild\rt.bat -p Win32 -d -q --fast-ci
+      run: .\PCbuild\rt.bat -p Win32 -d -q --fast-ci ${{ inputs.free-threaded && '--disable-gil' || '' }}
 
   build_win_amd64:
-    name: 'Windows (x64)'
+    name: 'x64'
     runs-on: windows-latest
     timeout-minutes: 60
     env:
@@ -32,10 +37,10 @@ jobs:
     - name: Display build info
       run: .\python.bat -m test.pythoninfo
     - name: Tests
-      run: .\PCbuild\rt.bat -p x64 -d -q --fast-ci
+      run: .\PCbuild\rt.bat -p x64 -d -q --fast-ci ${{ inputs.free-threaded && '--disable-gil' || '' }}
 
   build_win_arm64:
-    name: 'Windows (arm64)'
+    name: 'ARM64'
     runs-on: windows-latest
     timeout-minutes: 60
     env:
@@ -45,4 +50,4 @@ jobs:
     - name: Register MSVC problem matcher
       run: echo "::add-matcher::.github/problem-matchers/msvc.json"
     - name: Build CPython
-      run: .\PCbuild\build.bat -e -d -p arm64
+      run: .\PCbuild\build.bat -e -d -p arm64 ${{ inputs.free-threaded && '--disable-gil' || '' }}