tidy up Base.delayed_delete_dir() during Pkg.gc()

Author: IanButterworth

src/API.jl

@@ -1019,6 +1019,17 @@ function gc(ctx::Context=Context(); collect_delay::Period=Day(7), verbose=false,
         end
     end
 
+    # Delete any files that could not be rm-ed and were specially moved to the delayed delete directory.
+    # Do this silently because it's out of scope for Pkg.gc() but it's helpful to use this opportunity to do it
+    for p in readdir(Base.delayed_delete_dir(), join=true)
+        try
+            Base.Filesystem.prepare_for_deletion(p)
+            Base.rm(p; recursive=true, force=true, allow_delayed_delete=false)
+        catch e
+            @debug "Failed to delete $p" exception=e
+        end
+    end
+
     ndel_pkg = length(packages_to_delete)
     ndel_repo = length(repos_to_delete)
     ndel_art = length(artifacts_to_delete)