build: fix python search for gobject integration

When compiling with Gobject integration on Windows, the build fails because it finds the incorrect
python interpreter.

Closes: #265

.github/workflows/msvc-env.yml

@@ -9,15 +9,32 @@ on:
 jobs:
   build:
     runs-on: windows-latest
+    name: Build with introspection=${{ matrix.build_introspection }}
     env:
       PYTHONIOENCODING: "utf-8"
+      GIR_BUILD: ""
+    strategy:
+      fail-fast: false
+      matrix:
+        build_introspection: [ true, false ]
     steps:
     - uses: actions/checkout@master
     - uses: actions/setup-python@v1
     - uses: seanmiddleditch/gha-setup-vsdevenv@master
+    - name: Install GTK
+      if: matrix.build_introspection
+      run: |
+        $WebClient = New-Object System.Net.WebClient
+        $WebClient.DownloadFile("https://github.com/deluge-torrent/gvsbuild-release/releases/download/latest/gvsbuild-py3.10-vs16-x64.zip","C:\GTK.zip")
+        7z x C:\GTK.zip -oC:\GTK
+        echo "C:\GTK\release\lib" | Out-File -FilePath $env:GITHUB_PATH -Append
+        echo "C:\GTK\release\bin" | Out-File -FilePath $env:GITHUB_PATH -Append
+        echo "C:\GTK\release" | Out-File -FilePath $env:GITHUB_PATH -Append
+        echo "GIR_BUILD=-Dintrospection=enabled" >> $GITHUB_ENV
     - uses: BSFishy/[email protected]
       with:
         action: test
         directory: _build
+        setup-options: ${{ env.GIR_BUILD }}
         options: "--verbose"
         meson-version: "0.55.3"

src/meson.build

@@ -97,7 +97,7 @@ graphene_dep_sources = []
 
 # Introspection
 if build_gir
-  python = python.find_installation('python3')
+  python = python.find_installation()
   identfilter_py = join_paths(meson.current_source_dir(), 'identfilter.py')
 
   gir_extra_args = [