diff --git a/Makefile.pre.in b/Makefile.pre.in
index a6448a9c20e..dc635193076 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -286,8 +286,7 @@ platform: $(PYTHON)
 
 # Build the shared modules
 sharedmods: $(PYTHON)
-	PYTHONPATH= PYTHONHOME= PYTHONSTARTUP= \
-		./$(PYTHON) $(srcdir)/setup.py build
+	PYTHONPATH= ./$(PYTHON) $(srcdir)/setup.py build
 
 # buildno should really depend on something like LIBRARY_SRC
 buildno: $(PARSER_OBJS) \