#i114728# allow OSX platform SDKs that support OSX 10.7

Some newer Mac SDKs are backward compatible with OSX 10.7 deployment targets.
Allowing the build with newer compatible SDKs enables the use plain XCode,
even when XCode>= dropped the 10.7 SDK.


git-svn-id: https://svn.apache.org/repos/asf/openoffice/trunk@1562805 13f79535-47bb-0310-9956-ffa450edef68