Deal with symlinks in generated embeddings

Summary:
When embedding files into the redex Python environment, the Python `tarfile` support will create symlinks when the inputs are symlinks. That, of course, defeats the purpose.

Use `TarInfo` construction that avoids the issue.

Reviewed By: IanChilds

Differential Revision: D41507787

fbshipit-source-id: e72041d5d82e3166b23cd8deb1e9cea445173c2b

gen_packed_apilevels.py

@@ -69,9 +69,10 @@ def compress_tar_xz(inputs):
 
     for input in inputs:
         logging.info("Adding %s", input)
-        info = tar.gettarinfo(input)
-        info.name = os.path.basename(input)
+        # In case the inputs are symlinks, it's better to work with the file
+        # object outright.
         with open(input, "rb") as f:
+            info = tar.gettarinfo(arcname=os.path.basename(input), fileobj=f)
             tar.addfile(info, fileobj=f)
 
     tar.close()

gen_simple_module.py

@@ -69,9 +69,10 @@ def compress_tar_xz(inputs):
 
     for input in inputs:
         logging.info("Adding %s", input)
-        info = tar.gettarinfo(input)
-        info.name = os.path.basename(input)
+        # In case the inputs are symlinks, it's better to work with the file
+        # object outright.
         with open(input, "rb") as f:
+            info = tar.gettarinfo(arcname=os.path.basename(input), fileobj=f)
             tar.addfile(info, fileobj=f)
 
     tar.close()