build rsync from sources, to avoid divergence of protocols on various platforms;

--- a/etc/build.props	Wed Mar 29 21:28:48 2023 +0200
+++ b/etc/build.props	Wed Mar 29 22:21:12 2023 +0200
@@ -36,6 +36,7 @@
   src/Pure/Admin/component_polyml.scala \
   src/Pure/Admin/component_postgresql.scala \
   src/Pure/Admin/component_prismjs.scala \
+  src/Pure/Admin/component_rsync.scala \
   src/Pure/Admin/component_scala.scala \
   src/Pure/Admin/component_spass.scala \
   src/Pure/Admin/component_sqlite.scala \

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Pure/Admin/component_rsync.scala	Wed Mar 29 22:21:12 2023 +0200
@@ -0,0 +1,136 @@
+/*  Title:      Pure/Admin/component_rsync.scala
+    Author:     Makarius
+
+Build Isabelle rsync component from official source distribution.
+*/
+
+package isabelle
+
+
+object Component_Rsync {
+  /* build rsync */
+
+  val default_version = "3.2.7"
+  val default_download_url = "https://github.com/WayneD/rsync/archive/refs/tags"
+  val default_build_options =
+    "--disable-openssl --disable-xxhash --disable-zstd --disable-lz4 --disable-md2man"
+
+  def build_rsync(
+    version: String = default_version,
+    download_url: String = default_download_url,
+    progress: Progress = new Progress,
+    target_dir: Path = Path.current,
+    build_options: String = default_build_options
+  ): Unit = {
+    Isabelle_System.with_tmp_dir("build") { tmp_dir =>
+      /* component */
+
+      val component_name = "rsync-" + version
+      val component_dir =
+        Components.Directory(target_dir + Path.basic(component_name)).create(progress = progress)
+
+      val platform_name =
+        proper_string(Isabelle_System.getenv("ISABELLE_PLATFORM64"))
+          .getOrElse(error("No 64bit platform"))
+
+      val platform_dir =
+        Isabelle_System.make_directory(component_dir.path + Path.basic(platform_name))
+
+
+      /* download source */
+
+      val archive_name = "v" + version + ".tar.gz"
+      val archive_path = tmp_dir + Path.explode(archive_name)
+      val archive_url = Url.append_path(download_url, archive_name)
+      Isabelle_System.download_file(archive_url, archive_path, progress = progress)
+
+      Isabelle_System.extract(archive_path, tmp_dir)
+      val source_dir = File.get_dir(tmp_dir, title = archive_url)
+
+      Isabelle_System.extract(archive_path, component_dir.src, strip = true)
+
+
+      /* build */
+
+      progress.echo("Building rsync for " + platform_name + " ...")
+
+      val build_script = "./configure " + build_options + " && make"
+      Isabelle_System.bash(build_script, cwd = source_dir.file,
+        progress_stdout = progress.echo(_, verbose = true),
+        progress_stderr = progress.echo(_, verbose = true)).check
+
+
+      /* install */
+
+      Isabelle_System.copy_file(source_dir + Path.explode("COPYING"), component_dir.LICENSE)
+      Isabelle_System.copy_file(source_dir + Path.explode("rsync").platform_exe, platform_dir)
+
+
+      /* settings */
+
+      component_dir.write_settings("""
+ISABELLE_RSYNC_HOME="$COMPONENT/$ISABELLE_PLATFORM64"
+ISABELLE_RSYNC="$ISABELLE_RSYNC_HOME/rsync"
+""")
+
+
+      /* README */
+
+      File.write(component_dir.README,
+        "This is rsync " + version + " from " + download_url + """
+
+See also:
+  * https://github.com/WayneD/rsync
+  * https://rsync.samba.org
+
+The distribution has been built like this:
+
+    cd src && """ + build_script + """
+
+
+        Makarius
+        """ + Date.Format.date(Date.now()) + "\n")
+    }
+}
+
+
+  /* Isabelle tool wrapper */
+
+  val isabelle_tool =
+    Isabelle_Tool("component_rsync", "build rsync component from source distribution",
+      Scala_Project.here,
+      { args =>
+        var target_dir = Path.current
+        var version = default_version
+        var download_url = default_download_url
+        var verbose = false
+
+        val getopts = Getopts("""
+Usage: isabelle component_rsync [OPTIONS] [BUILD_OPTIONS ...]
+
+  Options are:
+    -D DIR       target directory (default ".")
+    -U URL       download URL
+                 (default: """" + default_download_url + """")
+    -V VERSION   version (default: """ + default_version + """)
+    -v           verbose
+
+  Build rsync component from the specified source distribution. The default
+  BUILD_OPTIONS are:
+
+  """ + default_build_options + "\n",
+          "D:" -> (arg => target_dir = Path.explode(arg)),
+          "U:" -> (arg => download_url = arg),
+          "V:" -> (arg => version = arg),
+          "v" -> (_ => verbose = true))
+
+        val more_args = getopts(args)
+        val build_options =
+          if (more_args.isEmpty) default_build_options else Bash.strings(more_args)
+
+        val progress = new Console_Progress(verbose = verbose)
+
+        build_rsync(version = version, download_url = download_url, progress = progress,
+          target_dir = target_dir, build_options = build_options)
+      })
+}

--- a/src/Pure/System/isabelle_tool.scala	Wed Mar 29 21:28:48 2023 +0200
+++ b/src/Pure/System/isabelle_tool.scala	Wed Mar 29 22:21:12 2023 +0200
@@ -179,6 +179,7 @@
   Component_PolyML.isabelle_tool2,
   Component_PostgreSQL.isabelle_tool,
   Component_Prismjs.isabelle_tool,
+  Component_Rsync.isabelle_tool,
   Component_SPASS.isabelle_tool,
   Component_SQLite.isabelle_tool,
   Component_Scala.isabelle_tool,