add small github actions script for a windows build

.github/workflows/windows_build.yml

@@ -0,0 +1,41 @@
+name: Native Windows CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+jobs:
+  build:
+    # https://github.com/actions/virtual-environments/blob/main/images/win/Windows2019-Readme.md
+    runs-on: windows-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Install pkg-config through chocolatey
+        run: choco install pkgconfiglite
+
+      - name: Download & build eigen lib
+        env:
+          THIRD_PARTY: packaging\win32_3rdparty
+        run: |
+          $third_party_path = "$env:GITHUB_WORKSPACE\packaging\win32_3rdparty"
+          Invoke-WebRequest -OutFile eigen.zip https://gitlab.com/libeigen/eigen/-/archive/3.3.8/eigen-3.3.8.zip
+          Expand-Archive -LiteralPath eigen.zip -DestinationPath $env:THIRD_PARTY
+          Set-Location -Path $env:THIRD_PARTY\eigen*
+          New-Item -ItemType "directory" -Path .\build
+          sl build
+          cmake -DCMAKE_INSTALL_PREFIX="${third_party_path}\" -DEIGEN_BUILD_PKGCONFIG=ON -Wno-dev ..
+          cmake --install .
+          md "${third_party_path}\lib\pkgconfig\"
+          cp "${third_party_path}\share\pkgconfig\eigen3.pc" -Destination "${third_party_path}\lib\pkgconfig\"
+          dir "${third_party_path}\lib\pkgconfig\"
+
+      - name: Configure build
+        run: |
+          python -X utf8 waf configure

wscript

@@ -130,8 +130,8 @@ def configure(ctx):
     # in gcc) instead of 387 floating point (used for 32-bit in gcc) to avoid
     # numerical differences between 32/64-bit builds
     # (see https://github.com/MTG/essentia/issues/179)
-    if (not ctx.options.EMSCRIPTEN and 
-        not ctx.options.CROSS_COMPILE_ANDROID and 
+    if (not ctx.options.EMSCRIPTEN and
+        not ctx.options.CROSS_COMPILE_ANDROID and
         not ctx.options.CROSS_COMPILE_IOS and
         not ctx.options.NO_MSSE and
         sys.platform != 'win32' and
@@ -200,7 +200,10 @@ def configure(ctx):
         ctx.env.LINKFLAGS += ['-pthread']
 
     elif sys.platform == 'win32':
-        print ("Building on win32")
+        print ("→ Building on win32: search for pre-built dependencies in 'packaging/win32_3rdparty'")
+
+        os.environ["PKG_CONFIG_PATH"] = 'packaging/win32_3rdparty/lib/pkgconfig'
+        os.environ["PKG_CONFIG_LIBDIR"] = os.environ["PKG_CONFIG_PATH"]
 
         """
         # compile libgcc and libstd statically when using MinGW
@@ -225,7 +228,7 @@ def configure(ctx):
         # force the use of mingw gcc compiler instead of msvc
         #ctx.env.CC = 'gcc'
         #ctx.env.CXX = 'g++'
-        
+
         import distutils.dir_util
 
         print("copying pkgconfig ...")
@@ -296,11 +299,11 @@ def configure(ctx):
     if ctx.env.STATIC_DEPENDENCIES \
         and (sys.platform.startswith('linux') or sys.platform == 'darwin') \
         and not ctx.options.CROSS_COMPILE_MINGW32:
-        
+
         if not ctx.env.ONLY_PYTHON:
             print ("→ Building with static dependencies on Linux/OSX")
             os.environ["PKG_CONFIG_PATH"] = 'packaging/debian_3rdparty/lib/pkgconfig'
-        
+
         # flags required for linking to static ffmpeg libs
         # -Bsymbolic flag is not available on clang
         if ctx.env.CXX_NAME != "clang":