issues :: what to do if I can't build apk on Linux

Today I can't because we have migrated to TargetFrameworkVersion v8.0 and I've got a new issue.

But I still can work with the PCL:

Easiest and fastest solution for me today is to build the apk using the macincloud (using the "x86" ABI for emulator and disabled the "Use Shared Mono Runtime" option), and then using the xfast.sh to work on Linux.

Normally I should try to fix the current Droid build issue, but I have not enough time yet.
I can't say does that library work or not, but now I can build and run the PCL.

Build error (Droid project):

Xamarin.Android.Common.targets (_UpdateAndroidResgen target) ->

.../Droid/obj/Debug/__library_projects__/Xamarin.Android.Support.Design/library_project_imports/res/values-v26/values-v26.xml(2): error APT0000:  Error: No resource found that matches the given name: attr 'android:keyboardNavigationCluster'.
.../Droid/obj/Debug/__library_projects__/Xamarin.Android.Support.v7.AppCompat/library_project_imports/res/values-v26/values-v26.xml(2): error APT0000:  Error: No resource found that matches the given name: attr 'android:keyboardNavigationCluster'