Upgrade from Kotlin 1.3.31 -> 1.3.40 breaks Android build

This behavior is the result of the recently fixed problem https://youtrack.jetbrains.com/issue/KT-19227. Previously, some built-in declarations like kotlin.Unit were loaded from the compiler internals when the compiled module didn't have a dependency on the Kotlin stdlib. Currently such a situation causes the build to fail, which is a less surprising behavior.

To make your project compile again, add the implementation(kotlin("stdlib")) dependency in your android subproject.