fix manifest

Signed-off-by: Dan Ryan <dan@danryan.co>

MANIFEST.in

@@ -15,6 +15,7 @@ include pipenv/vendor/pipreqs/stdlib pipenv/vendor/pipreqs/mapping
 include pipenv/vendor/*.txt pipenv/vendor/pexpect/bashrc.sh
 include pipenv/vendor/Makefile
 include pipenv/pipenv.1
+include .gitmodules
 exclude .editorconfig .travis.yml .env appveyor.yml tox.ini pytest.ini
 exclude Pipfile* CHANGELOG.draft.rst
 exclude docker-compose.yml Dockerfile

pipenv/vendor/vistir/misc.py

@@ -138,7 +138,6 @@ def _spawn_subprocess(script, env=None, block=True, cwd=None, combine_stderr=Tru
     return subprocess.Popen(script.cmdify(), **options)
 
 
-
 def _create_subprocess(
     cmd,
     env=None,
@@ -153,7 +152,7 @@ def _create_subprocess(
     write_to_stdout=True
 ):
     if not env:
-        env = {}
+        env = os.environ.copy()
     try:
         c = _spawn_subprocess(cmd, env=env, block=block, cwd=cwd,
                               combine_stderr=combine_stderr)