Plugin to work around include-files issue with AntlrTask

Plugin to work around these issues in the built-in AntlrTask in Gradle. The code works with Gradle 6.4.x and newer, it might work with earlier Gradle versions.

See these Gradle issues:

• antlr plugin should respect include files
• antlr-plugin should optionally be restricted to an explicit set of SourceSets
• AntlrTask doesn't respect non-default source-directories

Usage:

plugins {
    id("org.caffinitas.gradle.antlr") version "0.1"
}

The plugin disables all existing AntlrTasks. You need to register new tasks of the type CAntlrTask like this:

import org.caffinitas.gradle.antlr.CAntlrTask

val generateGrammarSourceCassandra by tasks.registering(CAntlrTask::class) {
    // find the "original" task and copy the configuration from that one
    val antlrTask = tasks.getByName("generateGrammarSource", AntlrTask::class)
    configureFrom(antlrTask)

    // add custom configurations (same as for the original AntlrTask)

    // specify the include files
    includeFiles = setOf("Lexer.g", "Parser.g")
}

Note: you cannot reuse a task name created by Gradle's built-in antlr-plugin.