rebuild rsync-3.2.7 on current platforms, including native arm64-darwin;
provide official etc/platforms.props, to retain platform directories after Components.Directory.clean() -- e.g. for SSH upload;

--- a/Admin/components/components.sha1	Thu Mar 28 11:45:45 2024 +0100
+++ b/Admin/components/components.sha1	Thu Mar 28 12:56:20 2024 +0100
@@ -441,6 +441,7 @@
 f132329ca1045858ef456cc08b197c9eeea6881b postgresql-9.4.1212.tar.gz
 3fc5e7f759e7220b9e3fc5bac296e312e34a60ad prismjs-1.29.0.tar.gz
 f042bba5fb82c7eb8aee99f92eb6ec38c8a067f7 python-3.10.4.tar.gz
+31d84d632faa216b8f9abf8e8591695e467fbb24 rsync-3.2.7-1.tar.gz
 d144120b7cf2d2b3106632af0b98c78278c467d7 rsync-3.2.7.tar.gz
 0885e1f1d8feaca78d2f204b6487e6eec6dfab4b scala-2.10.0.tar.gz
 f7dc7a4e1aea46408fd6e44b8cfacb33af61afbc scala-2.10.1.tar.gz

--- a/Admin/components/main	Thu Mar 28 11:45:45 2024 +0100
+++ b/Admin/components/main	Thu Mar 28 12:56:20 2024 +0100
@@ -29,7 +29,7 @@
 polyml-5.9.1
 postgresql-42.7.3
 prismjs-1.29.0
-rsync-3.2.7
+rsync-3.2.7-1
 scala-3.3.3
 smbc-0.4.1
 spass-3.8ds-2

--- a/src/Pure/Admin/component_rsync.scala	Thu Mar 28 11:45:45 2024 +0100
+++ b/src/Pure/Admin/component_rsync.scala	Thu Mar 28 12:56:20 2024 +0100
@@ -15,7 +15,7 @@
   def local_program: Path = Path.explode("$ISABELLE_RSYNC")
 
   def remote_program(directory: Components.Directory): Path = {
-    val platform = "platform_" + directory.ssh.isabelle_platform.ISABELLE_PLATFORM64
+    val platform = directory.ssh.isabelle_platform.ISABELLE_PLATFORM(apple = true)
     directory.path + Path.basic(platform) + Path.basic("rsync")
   }
 
@@ -46,11 +46,13 @@
 
       val component_name = "rsync-" + version
       val component_dir =
-        Components.Directory(target_dir + Path.basic(component_name)).create(progress = progress)
+        Components.Directory(target_dir + Path.basic(component_name))
+          .create(progress = progress)
+          .write_platforms()
 
-      val platform_name = Isabelle_Platform.self.ISABELLE_PLATFORM()
+      val platform_name = Isabelle_Platform.self.ISABELLE_PLATFORM(apple = true)
       val platform_dir =
-        Isabelle_System.make_directory(component_dir.path + Path.basic("platform_" + platform_name))
+        Isabelle_System.make_directory(component_dir.path + Path.basic(platform_name))
 
 
       /* download source */
@@ -86,7 +88,7 @@
 
       component_dir.write_settings("""
 ISABELLE_RSYNC_HOME="$COMPONENT"
-ISABELLE_RSYNC="$ISABELLE_RSYNC_HOME/platform_${ISABELLE_PLATFORM64}/rsync"
+ISABELLE_RSYNC="$ISABELLE_RSYNC_HOME/${ISABELLE_APPLE_PLATFORM64:-$ISABELLE_PLATFORM64}/rsync"
 """)