simplify code

Co-authored-by: Andrew Murray <3112309+radarhere@users.noreply.github.com>

winbuild/build_prepare.py

@@ -480,8 +480,8 @@ def extract_dep(url, filename):
             zf.extractall(sources_dir)
     elif filename.endswith(".tar.gz") or filename.endswith(".tgz"):
         with tarfile.open(file, "r:gz") as tgz:
-            for member in tgz.getmembers():
-                member_abspath = os.path.abspath(os.path.join(sources_dir, member.name))
+            for member in tgz.getnames():
+                member_abspath = os.path.abspath(os.path.join(sources_dir, member))
                 member_prefix = os.path.commonpath([sources_dir_abs, member_abspath])
                 if sources_dir_abs != member_prefix:
                     raise RuntimeError("Attempted Path Traversal in Tar File")