bltin_exc[]: EnvironmentError is not a "leaf exception", so set it's
leaf_exc flag to zero otherwise the name leaks memory.
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index b0d0648..7eb0f6a 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -2005,7 +2005,7 @@
 	{"AttributeError",     &PyExc_AttributeError,     1},
 	{"EOFError",           &PyExc_EOFError,           1},
 	{"FloatingPointError", &PyExc_FloatingPointError, 1},
-	{"EnvironmentError",   &PyExc_EnvironmentError,   1},
+	{"EnvironmentError",   &PyExc_EnvironmentError,   0},
 	{"IOError",            &PyExc_IOError,            1},
 	{"OSError",            &PyExc_OSError,            1},
 	{"ImportError",        &PyExc_ImportError,        1},