mark_service: symlink rather then duplicate multicall binary

As done with einfo, rather then have many copies of the same executable,
that differ in only name, create a single copy and symlink all the
others.

src/mark_service/meson.build

@@ -1,5 +1,4 @@
 mark_service_execs =	[
-  'mark_service_starting',
   'mark_service_started',
   'mark_service_stopping',
   'mark_service_stopped',
@@ -10,11 +9,18 @@ mark_service_execs =	[
   'mark_service_crashed',
   ]
 
+executable('mark_service_starting',
+  ['mark_service.c', misc_c, version_h],
+  include_directories: [incdir, einfo_incdir, rc_incdir],
+  link_with: [libeinfo,librc],
+  install: true,
+  install_dir: rc_sbindir)
+
 foreach exec : mark_service_execs
-  executable(exec,
-    ['mark_service.c', misc_c, version_h],
-    include_directories: [incdir, einfo_incdir, rc_incdir],
-    link_with: [libeinfo,librc],
+  custom_target(exec,
+    output: exec,
+    command: ['ln', '-sf', 'mark_service_starting', '@OUTPUT@'],
+    build_always: true,
     install: true,
     install_dir: rc_sbindir)
 endforeach