1 files changed, 2 insertions, 1 deletions
diff --git a/setup.py b/setup.py
index ef10ca1..8879c5c 100644
--- a/setup.py
+++ b/setup.py
@@ -79,11 +79,12 @@ else:
     py_impl = getattr(platform, 'python_implementation', lambda: None)
     is_pypy = py_impl() == 'PyPy'
     is_jython = 'java' in sys.platform
+    is_pure = 'PURE_PYTHON' in os.environ
 
     # Jython cannot build the C optimizations, while on PyPy they are
     # anti-optimizations (the C extension compatibility layer is known-slow,
     # and defeats JIT opportunities).
-    if is_pypy or is_jython:
+    if is_pypy or is_jython or is_pure:
         features = {}
     else:
         features = {'codeoptimization': codeoptimization}