The initialization of posix_putenv_garbage should only be done when it
is defined...
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 7736ac3..20170d6 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -4783,5 +4783,7 @@
 
 	PyDict_SetItemString(d, "error", PyExc_OSError);
 
+#ifdef HAVE_PUTENV
 	posix_putenv_garbage = PyDict_New();
+#endif
 }