Fixups to get GenAPI running

GenAPI is super fickle.  It doesn't like some trailing slashes in some cases, or ; instead of , as a path separator.  Also, looks like the v4 project was missing some expected msbuild properties when invoked from the command line on incremental builds, so hard coded things like the intermediate output path and the v9.0 / monoandroid90 framework version which we'll need to eventually bump (maybe not since there are no more support libs?).

Author: Redth

source/AndroidSupportProject.cshtml

@@ -168,7 +168,17 @@
     <Target Name="AndroidSupportLibrariesTypeForwardersGenerationWithGenAPI" BeforeTargets="Build">
       <Message Text="AndroidSupportLibrariesTypeForwardersGenerationWithGenAPI" ></Message>
       <PropertyGroup>
-        <GenAPIPath>$(MSBuildProjectDirectory)/../../tools/microsoft.dotnet.buildtools.genapi.1.0.0-beta-00081/Microsoft.DotNet.BuildTools.GenAPI/tools/GenAPI.exe</GenAPIPath>
+        <GenAPITargetFramework>$(TargetFramework)</GenAPITargetFramework>
+        <GenAPITargetFramework Condition=" '$(GenAPITargetFramework)' == '' ">$(TargetFrameworks)</GenAPITargetFramework>
+        <GenAPIPath>$(MSBuildProjectDirectory)\..\..\tools\microsoft.dotnet.buildtools.genapi.1.0.0-beta-00081\Microsoft.DotNet.BuildTools.GenAPI\tools\GenAPI.exe</GenAPIPath>
+        
+        <GenAPIIntermediateOutputPath>bin\Release\MonoAndroid90\</GenAPIIntermediateOutputPath>
+
+        <GenAPILibPaths Condition=" '$(OS)' == 'Windows_NT' ">$(VsInstallRoot)\Common7\IDE\ReferenceAssemblies\Microsoft\Framework\MonoAndroid\v1.0,$(VsInstallRoot)\Common7\IDE\ReferenceAssemblies\Microsoft\Framework\MonoAndroid\v9.0</GenAPILibPaths>
+        <GenAPILibPaths Condition=" '$(OS)' != 'Windows_NT' ">$(VsInstallRoot)\Common7\IDE\ReferenceAssemblies\Microsoft\Framework\MonoAndroid\v1.0,$(VsInstallRoot)\Common7\IDE\ReferenceAssemblies\Microsoft\Framework\MonoAndroid\v9.0</GenAPILibPaths>
+
+        <GenAPICommand Condition=" '$(OS)' == 'Windows_NT'">"$(GenAPIPath)"</GenAPICommand>
+        <GenAPICommand Condition=" '$(OS)' != 'Windows_NT'">mono --runtime=v4.0.30319 "$(GenAPIPath)"</GenAPICommand>
       </PropertyGroup>
 
       <ItemGroup>
@@ -177,10 +187,9 @@
             if (dep.IsProjectReference) 
             {
               <GenAPIItemBase 
-                Include="../../generated/@(dep.MavenArtifact.MavenGroupId).@(dep.MavenArtifact.MavenArtifactId)/"
-                >
-                <GenAPIAssembly>"$(IntermediateOutputPath)/@(dep.NuGetPackageId).dll"</GenAPIAssembly>
-                <GenAPICSCode>./Additions/@(dep.NuGetPackageId).cs</GenAPICSCode>
+                Include="$(MSBuildProjectDirectory)\..\@(dep.MavenArtifact.MavenGroupId).@(dep.MavenArtifact.MavenArtifactId)\">
+                <GenAPIAssembly>$(GenAPIIntermediateOutputPath)@(dep.NuGetPackageId).dll</GenAPIAssembly>
+                <GenAPICSCode>$(MSBuildProjectDirectory)\Additions\@(dep.NuGetPackageId).cs</GenAPICSCode>
               </GenAPIItemBase>
             }
         }
@@ -191,9 +200,9 @@
       // For some reason GenAPI.exe can't handle absolute paths on mac/unix properly, so always make them relative
       // GenAPI.exe -libPath:$(MONOANDROID) -out:Some.generated.cs -w:TypeForwards ./relative/path/to/Assembly.dll
       -->
-      <MakeDir Directories="./Additions" />         
+      <MakeDir Directories="$(MSBuildProjectDirectory)\Additions" />         
       <Exec
-        Command="mono $(GenAPIPath) -libPath:$(MONOANDROID) -out:%(GenAPIItemBase.GenAPICSCode) -w:TypeForwards %(GenAPIItemBase.Identity)/%(GenAPIItemBase.GenAPIAssembly) " 
+        Command="$(GenAPIPath) -libPath:&quot;$(GenAPILibPaths)&quot; -out:&quot;%(GenAPIItemBase.GenAPICSCode)&quot; -w:TypeForwards &quot;%(GenAPIItemBase.Identity)%(GenAPIItemBase.GenAPIAssembly)&quot;" 
         />
     </Target>
   }