Visible java icon in mac os dock when building kotlin project

[oliviernotteghem]

This is most likely due to non running java command in headless mode on one of the actions created by kotlin rules.

[Bencodes]

You can work around this by doing:

# Avoid popping up the Java GUI in the macos dock
build --host_jvmopt="-Dapple.awt.UIElement=true" --jvmopt="-Dapple.awt.UIElement=true"

Upstream Bazel should probably just pass these flags by defualt.