diff --git a/bob/buildout/envwrapper.py b/bob/buildout/envwrapper.py
index 346aa9a122b71fc3e8ffbad9e1a50159147a7707..a0ab0fd033e79086d2eb64184b5c5398705356c5 100644
--- a/bob/buildout/envwrapper.py
+++ b/bob/buildout/envwrapper.py
@@ -28,7 +28,7 @@ class EnvironmentWrapper(object):
 
   # Note: CLang does not work well with BZ_DEBUG
   if platform.system() != 'Darwin':
-    DEBUG_FLAGS += " -DBZ_DEBUG"
+    DEBUG_CFLAGS += " -DBZ_DEBUG"
 
   def __init__(self, logger, debug=None, prefixes=None, environ=None):