Publish executables for pkldoc, pkl-codegen-java, pkl-codegen-kotlin (#1023)

This adds logic to build and publish the other executables related to Pkl.

These are:

* pkl-doc
* pkl-codegen-kotlin
* pkl-codegen-java

pkl-codegen-kotlin and pkl-codegen-java are published as executable JARs, whereas pkldoc is published both as an executable JAR, and also native executables (matching the set of os/arch supported by Pkl).

The reason this only publishes executable JARs for pkl-codegen-kotlin and pkl-codegen-java is because we expect that the Java requirement is not a problem for these users, and that the native executable provides negligible added value.

As part of this, the following changes are made:

* Introduce `pklJavaExecutable` plugin, which sets up building and publishing of executable JAR.
* Introduce `pklNativeExecutable` plugin, which sets up building and publishing of native executables.
* Introduce `NativeImageBuild` Gradle task, which knows how to build native-image executables.
* Introduce `ExecutableSpec` extension, for projects that publish executables to configure how those executables should be published.
* `./griddles buildNative`, by default, will only build the executable of the host OS/Arch, and will no longer cross-build.
* The target arch of `./gradlew buildNative` can be changed using `-Dpkl.targetArch=<aarch64|amd64>`.
* On linux/amd64 only, with `./gradlew buildNative`, a statically linked executable can be built using `-Dpkl.musl=true`
* Make `javaExecutable` a dependency of `assemble`
* Make `testStartJavaExecutable` a dependency of `check`
* Change name `pklNativeBuild` to `pklNativeLifecycle` to better match the plugin's purpose
* Remove Truffle SVM classes from main source set (don't publish these classes as part of the pkl-cli JAR)
* Change CircleCI definition to publish new executables
* Change CircleCI definition to call `buildNative` instead of individual task names

docs/modules/pkl-doc/pages/index.adoc

@@ -5,6 +5,23 @@ include::ROOT:partial$component-attributes.adoc[]
 :uri-DocPackageInfo: {uri-pkl-stdlib-docs}/DocPackageInfo/
 :uri-CliDocGenerator: {uri-pkl-doc-main-sources}/CliDocGenerator.kt
 :uri-DocGenerator: {uri-pkl-doc-main-sources}/DocGenerator.kt
+:uri-pkldoc-macos-amd64-download: {uri-sonatype-snapshot-download}&a=pkldoc-macos-amd64&e=bin
+:uri-pkldoc-macos-aarch64-download: {uri-sonatype-snapshot-download}&a=pkldoc-macos-aarch64&e=bin
+:uri-pkldoc-linux-amd64-download: {uri-sonatype-snapshot-download}&a=pkldoc-linux-amd64&e=bin
+:uri-pkldoc-linux-aarch64-download: {uri-sonatype-snapshot-download}&a=pkldoc-linux-aarch64&e=bin
+:uri-pkldoc-alpine-download: {uri-sonatype-snapshot-download}&a=pkldoc-alpine-linux-amd64&e=bin
+:uri-pkldoc-windows-download: {uri-sonatype-snapshot-download}&a=pkldoc-windows-amd64&e=exe
+:uri-pkldoc-java-download: {uri-sonatype-snapshot-download}&a=pkldoc-java&e=jar
+
+ifdef::is-release-version[]
+:uri-pkldoc-macos-amd64-download: {github-releases}/pkldoc-macos-amd64
+:uri-pkldoc-macos-aarch64-download: {github-releases}/pkldoc-macos-aarch64
+:uri-pkldoc-linux-amd64-download: {github-releases}/pkldoc-linux-amd64
+:uri-pkldoc-linux-aarch64-download: {github-releases}/pkldoc-linux-aarch64
+:uri-pkldoc-alpine-download: {github-releases}/pkldoc-alpine-linux-amd64
+:uri-pkldoc-windows-download: {github-releases}/pkldoc-windows-amd64.exe
+:uri-pkldoc-java-download: {github-releases}/jpkldoc
+endif::[]
 
 _Pkldoc_ is a documentation website generator that produces navigable and searchable API documentation for Pkl modules.
 
@@ -153,8 +170,33 @@ endif::[]
 [[install-cli]]
 === CLI
 
-The CLI is bundled with the library and does not currently ship as a native executable or a self-contained Jar.
-We recommend to provision it with a Maven compatible build tool as shown in <<install-library,Library Installation>>.
+The CLI comes in multiple flavors:
+
+* Native macOS executable for amd64 (tested on macOS 10.15)
+* Native Linux executable for amd64
+* Native Linux executable for aarch64
+* Native Alpine Linux executable for amd64 (cross-compiled and tested on Oracle Linux 8)
+* Native Windows executable for amd64 (tested on Windows Server 2022)
+* Java executable (tested with Java 17/21 on macOS and Oracle Linux)
+
+.What is the Difference Between the Linux and Alpine Linux Executables?
+[NOTE]
+====
+The Linux executable is dynamically linked against _glibc_ and _libstdc{plus}{plus}_,
+whereas, the Alpine Linux executable is statically linked against _musl libc_ and _libstdc{plus}{plus}_.
+====
+
+The Java executable works on multiple platforms and has a smaller binary size than the native executables.
+However, it requires a Java 17 (or higher) runtime on the system path, and has a noticeable startup delay.
+
+Download links:
+
+* macOS aarch64: {uri-pkldoc-macos-aarch64-download}
+* macOS amd64: {uri-pkldoc-macos-amd64-download}
+* Linux aarch64: {uri-pkldoc-linux-aarch64-download}
+* Linux amd64: {uri-pkldoc-linux-amd64-download}
+* Alpine Linux amd64: {uri-pkldoc-alpine-download}
+* Windows amd64: {uri-pkldoc-windows-download}
 
 [[usage]]
 == Usage
@@ -216,10 +258,7 @@ For more information, refer to the Javadoc documentation.
 
 === CLI
 
-As mentioned in <<install-cli,CLI Installation>>, the CLI is bundled with the library.
-To run the CLI, execute the library Jar or its `org.pkl.doc.Main` class.
-
-*Synopsis:* `java -cp <classpath> -jar pkl-doc.jar [<options>] <modules>`
+*Synopsis:* `pkldoc [<options>] <modules>`
 
 `<modules>`::
 The absolute or relative URIs of docsite descriptors, package descriptors, and the modules for which to generate documentation.
@@ -252,4 +291,4 @@ include::../../pkl-cli/partials/cli-common-options.adoc[]
 == Full Example
 
 For a ready-to-go example with full source code and detailed walkthrough,
-see link:{uri-pkldoc-example}[pkldoc] in the _pkl/pkl-examples_ repository.
+see link:{uri-pkldoc-example}[pkldoc] in the _pkl-jvm-examples_ repository.