setup.py: add parent to sys.path

When using pyproject.toml the parent of setup.py
is not on sys.path by default.

See <https://github.com/pypa/setuptools/discussions/3134>

1 files changed, 1 insertions, 0 deletions

diff --git a/setup.py b/setup.py
index 98a844269..977035d7d 100644
--- a/setup.py
+++ b/setup.py
@@ -19,6 +19,7 @@ try:
 except ImportError:
     cythonize = None
 
+sys.path += [os.path.dirname(__file__)]
 import setup_checksums
 import setup_compress
 import setup_crypto