Support for additional launchers

[alchitry]

For my application I need the installer to include two launchers with different arguments. It turns out JPackage supports this so I added support to add the necessary flags.

WIth this addition, you can specify additional launchers in the nativeDistributions block like this.

compose.desktop {
    application {
        mainClass = "com.alchitry.labs.MainKt"
        nativeDistributions {
            targetFormats(TargetFormat.Dmg, TargetFormat.Msi, TargetFormat.Deb)
            packageName = "Alchitry Labs"
            packageVersion = (version as String).split("-").first()
            vendor = "Alchitry"

            additionalLauncher("Alchitry Loader") {
                add("arguments","loader")
            }
        }
    }
}

You pass arguments to add to the properties file through the add function.

Here's the relevant doc for the add-launcher flag.

--add-launcher name=path
Name of launcher, and a path to a Properties file that contains a list of key, value pairs

(absolute path or relative to the current directory)

The keys "module", "main-jar", "main-class", "description", "arguments", "java-options", "app-version", "icon", "launcher-as-service", "win-console", "win-shortcut", "win-menu", "linux-app-category", and "linux-shortcut" can be used.

These options are added to, or used to overwrite, the original command line options to build an additional alternative launcher. The main application launcher will be built from the command line options. Additional alternative launchers can be built using this option, and this option can be used multiple times to build multiple additional launchers.

[amir1376]

i also need that feature.Thanks