Introduce libexec folder in the distribution (#21427)

As of now, when installing scala and adding the `/bin` directory to
`PATH`, the `common`, `cli-common-platform` and `common-shared` scripts
are also added. This PR moves the following script to the `libexec`
folder to avoid the addition of the scripts.

dist/bin/scala

@@ -26,8 +26,8 @@ if [ -z "${PROG_HOME-}" ] ; then
   cd "$saveddir"
 fi
 
-source "$PROG_HOME/bin/common-shared"
-source "$PROG_HOME/bin/cli-common-platform"
+source "$PROG_HOME/libexec/common-shared"
+source "$PROG_HOME/libexec/cli-common-platform"
 
 SCALA_VERSION=""
 # iterate through lines in VERSION_SRC

dist/bin/scala.bat

@@ -11,15 +11,15 @@ for %%f in ("%~dp0.") do (
     @rem get rid of the trailing slash
     set "_PROG_HOME=!_PROG_HOME:~0,-1!"
 )
-call "%_PROG_HOME%\bin\common.bat"
+call "%_PROG_HOME%\libexec\common.bat"
 if not %_EXITCODE%==0 goto end
 
 @rem #########################################################################
 @rem ## Main
 
 call :setScalaOpts
 
-call "%_PROG_HOME%\bin\cli-common-platform.bat"
+call "%_PROG_HOME%\libexec\cli-common-platform.bat"
 
 @rem SCALA_CLI_CMD_WIN is an array, set in cli-common-platform.bat.
 @rem WE NEED TO PASS '--skip-cli-updates' for JVM launchers but we actually don't need it for native launchers

dist/bin/scala_legacy

@@ -26,7 +26,7 @@ if [ -z "${PROG_HOME-}" ] ; then
   cd "$saveddir"
 fi
 
-source "$PROG_HOME/bin/common"
+source "$PROG_HOME/libexec/common"
 
 while [[ $# -gt 0 ]]; do
   case "$1" in

dist/bin/scalac

@@ -26,7 +26,7 @@ if [ -z "${PROG_HOME-}" ] ; then
   cd "$saveddir"
 fi
 
-source "$PROG_HOME/bin/common"
+source "$PROG_HOME/libexec/common"
 
 [ -z "$PROG_NAME" ] && PROG_NAME=$CompilerMain
 

dist/bin/scalac.bat

@@ -11,7 +11,7 @@ for %%f in ("%~dp0.") do (
     @rem get rid of the trailing slash
     set "_PROG_HOME=!_PROG_HOME:~0,-1!"
 )
-call "%_PROG_HOME%\bin\common.bat"
+call "%_PROG_HOME%\libexec\common.bat"
 if not %_EXITCODE%==0 goto end
 
 call :args %*

dist/bin/scaladoc

@@ -28,7 +28,7 @@ if [ -z "${PROG_HOME-}" ] ; then
   cd "$saveddir"
 fi
 
-source "$PROG_HOME/bin/common"
+source "$PROG_HOME/libexec/common"
 default_java_opts="-Xmx768m -Xms768m"
 withCompiler=true
 

dist/bin/scaladoc.bat

@@ -11,7 +11,7 @@ for %%f in ("%~dp0.") do (
     @rem get rid of the trailing slash
     set "_PROG_HOME=!_PROG_HOME:~0,-1!"
 )
-call "%_PROG_HOME%\bin\common.bat"
+call "%_PROG_HOME%\libexec\common.bat"
 if not %_EXITCODE%==0 goto end
 
 set _DEFAULT_JAVA_OPTS=-Xmx768m -Xms768m

dist/libexec-native-overrides/cli-common-platform

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+SCALA_CLI_CMD_BASH=("\"$PROG_HOME/libexec/scala-cli\"")

dist/libexec-native-overrides/cli-common-platform.bat

@@ -0,0 +1,3 @@
+@echo off
+
+set SCALA_CLI_CMD_WIN="%_PROG_HOME%\libexec\scala-cli.exe"

dist/bin/common → dist/libexec/common

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-source "$PROG_HOME/bin/common-shared"
+source "$PROG_HOME/libexec/common-shared"
 
 #/*--------------------------------------------------
 # * The code below is for Dotty

project/Build.scala

@@ -2137,9 +2137,10 @@ object Build {
     Universal / packageBin := (Universal / packageBin).dependsOn(republish).value,
     Universal / packageZipTarball := (Universal / packageZipTarball).dependsOn(republish).value,
     // ========
-    Universal / mappings ++= directory(republishRepo.value / "bin"),
+    Universal / mappings ++= directory(dist.base / "bin"),
     Universal / mappings ++= directory(republishRepo.value / "maven2"),
     Universal / mappings ++= directory(republishRepo.value / "lib"),
+    Universal / mappings ++= directory(republishRepo.value / "libexec"),
     Universal / mappings +=  (republishRepo.value / "VERSION") -> "VERSION",
     // ========
     republishCommandLibs += ("scala" -> List("scala3-interfaces", "scala3-compiler", "scala3-library", "tasty-core")),
@@ -2150,7 +2151,7 @@ object Build {
   lazy val dist = project.asDist(Bootstrapped)
     .settings(packageName := "scala3-" + dottyVersion)
     .settings(
-      republishBinDir := baseDirectory.value / "bin",
+      republishLibexecDir := baseDirectory.value / "libexec",
       republishCoursier +=
         ("coursier.jar" -> s"https://github.com/coursier/coursier/releases/download/v$coursierJarVersion/coursier.jar"),
       republishLaunchers +=
@@ -2160,8 +2161,8 @@ object Build {
   lazy val `dist-mac-x86_64` = project.in(file("dist/mac-x86_64")).asDist(Bootstrapped)
     .settings(packageName := (dist / packageName).value + "-x86_64-apple-darwin")
     .settings(
-      republishBinDir := (dist / republishBinDir).value,
-      republishBinOverrides += (dist / baseDirectory).value / "bin-native-overrides",
+      republishLibexecDir := (dist / republishLibexecDir).value,
+      republishLibexecOverrides += (dist / baseDirectory).value / "libexec-native-overrides",
       republishFetchCoursier := (dist / republishFetchCoursier).value,
       republishLaunchers +=
         ("scala-cli" -> s"gz+https://github.com/VirtusLab/scala-cli/releases/download/v$scalaCliLauncherVersion/scala-cli-x86_64-apple-darwin.gz")
@@ -2170,8 +2171,8 @@ object Build {
   lazy val `dist-mac-aarch64` = project.in(file("dist/mac-aarch64")).asDist(Bootstrapped)
     .settings(packageName := (dist / packageName).value + "-aarch64-apple-darwin")
     .settings(
-      republishBinDir := (dist / republishBinDir).value,
-      republishBinOverrides += (dist / baseDirectory).value / "bin-native-overrides",
+      republishLibexecDir := (dist / republishLibexecDir).value,
+      republishLibexecOverrides += (dist / baseDirectory).value / "libexec-native-overrides",
       republishFetchCoursier := (dist / republishFetchCoursier).value,
       republishLaunchers +=
         ("scala-cli" -> s"gz+https://github.com/VirtusLab/scala-cli/releases/download/v$scalaCliLauncherVersion/scala-cli-aarch64-apple-darwin.gz")
@@ -2181,8 +2182,8 @@ object Build {
     .enablePlugins(WindowsPlugin) // TO GENERATE THE `.msi` installer
     .settings(packageName := (dist / packageName).value + "-x86_64-pc-win32")
     .settings(
-      republishBinDir := (dist / republishBinDir).value,
-      republishBinOverrides += (dist / baseDirectory).value / "bin-native-overrides",
+      republishLibexecDir := (dist / republishLibexecDir).value,
+      republishLibexecOverrides += (dist / baseDirectory).value / "libexec-native-overrides",
       republishFetchCoursier := (dist / republishFetchCoursier).value,
       republishLaunchers +=
         ("scala-cli.exe" -> s"zip+https://github.com/VirtusLab/scala-cli/releases/download/v$scalaCliLauncherVersion/scala-cli-x86_64-pc-win32.zip!/scala-cli.exe")
@@ -2204,8 +2205,8 @@ object Build {
   lazy val `dist-linux-x86_64` = project.in(file("dist/linux-x86_64")).asDist(Bootstrapped)
     .settings(packageName := (dist / packageName).value + "-x86_64-pc-linux")
     .settings(
-      republishBinDir := (dist / republishBinDir).value,
-      republishBinOverrides += (dist / baseDirectory).value / "bin-native-overrides",
+      republishLibexecDir := (dist / republishLibexecDir).value,
+      republishLibexecOverrides += (dist / baseDirectory).value / "libexec-native-overrides",
       republishFetchCoursier := (dist / republishFetchCoursier).value,
       republishLaunchers +=
         ("scala-cli" -> s"gz+https://github.com/VirtusLab/scala-cli/releases/download/v$scalaCliLauncherVersion/scala-cli-x86_64-pc-linux.gz")
@@ -2214,8 +2215,8 @@ object Build {
   lazy val `dist-linux-aarch64` = project.in(file("dist/linux-aarch64")).asDist(Bootstrapped)
     .settings(packageName := (dist / packageName).value + "-aarch64-pc-linux")
     .settings(
-      republishBinDir := (dist / republishBinDir).value,
-      republishBinOverrides += (dist / baseDirectory).value / "bin-native-overrides",
+      republishLibexecDir := (dist / republishLibexecDir).value,
+      republishLibexecOverrides += (dist / baseDirectory).value / "libexec-native-overrides",
       republishFetchCoursier := (dist / republishFetchCoursier).value,
       republishLaunchers +=
         ("scala-cli" -> s"gz+https://github.com/VirtusLab/scala-cli/releases/download/v$scalaCliLauncherVersion/scala-cli-aarch64-pc-linux.gz")

project/RepublishPlugin.scala

@@ -60,9 +60,9 @@ object RepublishPlugin extends AutoPlugin {
     val republishFetchCoursier = taskKey[File]("cache the coursier.jar for resolving the local maven repo.")
     val republishPrepareBin = taskKey[File]("prepare the bin directory, including launchers and scripts.")
     val republishWriteExtraProps = taskKey[Option[File]]("write extra properties for the launchers.")
-    val republishBinDir = settingKey[File]("where to find static files for the bin dir.")
+    val republishLibexecDir = settingKey[File]("where to find static files for the `libexec` dir.")
     val republishCoursierDir = settingKey[File]("where to download the coursier launcher jar.")
-    val republishBinOverrides = settingKey[Seq[File]]("files to override those in bin-dir.")
+    val republishLibexecOverrides = settingKey[Seq[File]]("files to override those in libexec-dir.")
     val republishCommandLibs = settingKey[Seq[(String, List[String])]]("libraries needed for each command.")
     val republish = taskKey[File]("cache the dependencies and download launchers for the distribution")
     val republishPack = taskKey[File]("do the pack command")
@@ -405,7 +405,7 @@ object RepublishPlugin extends AutoPlugin {
     republishCoursierDir := republishRepo.value / "coursier",
     republishLaunchers := Seq.empty,
     republishCoursier := Seq.empty,
-    republishBinOverrides := Seq.empty,
+    republishLibexecOverrides := Seq.empty,
     republishExtraProps := Seq.empty,
     republishCommandLibs := Seq.empty,
     republishLocalResolved / republishProjectRefs := {
@@ -489,16 +489,14 @@ object RepublishPlugin extends AutoPlugin {
     },
     republishPrepareBin := {
       val baseDir = baseDirectory.value
-      val srcBin = republishBinDir.value
-      val overrides = republishBinOverrides.value
+      val srcLibexec = republishLibexecDir.value
+      val overrides = republishLibexecOverrides.value
       val repoDir = republishRepo.value
 
-      val targetBin = repoDir / "bin"
-      IO.copyDirectory(srcBin, targetBin)
-      overrides.foreach { dir =>
-        IO.copyDirectory(dir, targetBin, overwrite = true)
-      }
-      targetBin
+      val targetLibexec = repoDir / "libexec"
+      IO.copyDirectory(srcLibexec, targetLibexec)
+      overrides.foreach(IO.copyDirectory(_, targetLibexec, overwrite = true))
+      targetLibexec
     },
     republishWriteExtraProps := {
       val s = streams.value