building an apk with gradle on macOS

I wanted to build Conversations on my macOS box, but never did modern Android stuff before. It turned out it was (quite) simple to do.

(I already had jenv (brew install jenv) and Java 8 (brew cask install java8) installed)

$ jenv global 1.8.0.202 # depends on the exact version you have
$ brew install android-sdk
…
$ yes|sdkmanager --licenses

Afterwards, you can build Conversations using the contained gradle wrapper:

$ ./gradlew assembleConversationsFreeSystemDebug

During signing this bailed, however, due to me having an older version of bouncycastle installed in /Library/Java/Extensions. Version 152 wasn't good enough, but 162 is.