Automatically build Mediapipe native libraries during dotnet build (#58)

* Added PreBuildEvent to Linux runtime project

* Added PreBuildEvent to Windows runtime project

* Fix dumb Powershell error

* Remove quotes

* Test PowerShell before building

* Fix path

* Putting expression in quotes to see what happens

* Only test on Windows

* Temporarily not building on Windows

* Remove Test Powershell on CI

* Bring back quotesand print PSVersionTable

* Use Batch syntax instead of Powershell syntax

* Uncomment Windows .NET Build task on CI

Author: Speykious

src/Runtime/Akihabara.Runtime.Linux_x64.CPU/Akihabara.Runtime.Linux_x64.CPU.csproj

@@ -21,6 +21,15 @@
     <IncludeBuildOutput>false</IncludeBuildOutput>
   </PropertyGroup>
 
+  <PropertyGroup Label="Pre-build task">
+    <PreBuildEvent>
+      if [ ! -f $(MSBuildProjectDirectory)/libmediapipe_c.so ]; then
+        cd $(MSBuildProjectDirectory)/../../../
+        python3 build.py build --desktop cpu -v
+      fi
+    </PreBuildEvent>
+  </PropertyGroup>
+
   <ItemGroup>
     <!-- I didn't think it would be this criminally simple to include the native library -->
     <Content Include="*.so" Pack="true" PackagePath="lib\$(TargetFramework)">

src/Runtime/Akihabara.Runtime.Windows_x64.CPU/Akihabara.Runtime.Windows_x64.CPU.csproj

@@ -21,6 +21,15 @@
     <IncludeBuildOutput>false</IncludeBuildOutput>
   </PropertyGroup>
 
+  <PropertyGroup Label="Pre-build task">
+    <PreBuildEvent>
+      if not exist "$(MSBuildProjectDirectory)\libmediapipe_c.dll" (
+          cd $(MSBuildProjectDirectory)\..\..\..\
+          python3 build.py build --desktop cpu -v
+      )
+    </PreBuildEvent>
+  </PropertyGroup>
+
   <ItemGroup>
     <!-- I didn't think it would be this criminally simple to include the native library -->
     <Content Include="*.dll" Pack="true" PackagePath="lib\$(TargetFramework)">