Tentative fix for pi having wrong value on one platform.

Fix non-conforming call to atan2(0,0).


[SVN r31587]

libs/math

@@ -1 +1 @@
-Subproject commit 974a55463e0883678ae48e550b8b520a15721940
+Subproject commit fc99ec6f69775d105f056b933c59a8aa6881ba68