Reintrocude optional and print more info

Author: minhqdao

src/fpm/dependency.f90

@@ -514,7 +514,7 @@ subroutine get_from_registry(self, target_dir, global_settings, error, downloade
     type(error_t), allocatable, intent(out) :: error
 
     !> Downloader instance.
-    class(downloader_t), intent(in) :: downloader
+    class(downloader_t), optional, intent(in) :: downloader
 
     character(:), allocatable :: cache_path, target_url, tmp_file, tmp_path
     type(version_t) :: version

src/fpm/downloader.f90

@@ -84,6 +84,7 @@ subroutine unpack(tmp_file, destination, error)
       call fatal_error(error, "'tar' not installed."); return
     end if
 
+    print *, "Unpacking '"//tmp_file//"' to '"//destination//"' ..."
     call execute_command_line('tar -zxf '//tmp_file//' -C '//destination, exitstat=stat)
 
     if (stat /= 0) then