pass through the env vars we need in tox for alternate OpenSSL builds
INCLUDE and LIB are used in windows
ARCHFLAGS CFLAGS LDFLAGS are used on OS X
CFLAGS LDFLAGS LD_LIBRARY_PATH are used on linux
diff --git a/tox.ini b/tox.ini
index 759345f..77382eb 100644
--- a/tox.ini
+++ b/tox.ini
@@ -9,6 +9,7 @@
pretend
pytest
./vectors
+passenv = ARCHFLAGS LDFLAGS CFLAGS INCLUDE LIB LD_LIBRARY_PATH
commands =
# We use parallel mode and then combine here so that coverage.py will take
# the paths like .tox/py34/lib/python3.4/site-packages/cryptography/__init__.py