Undefine near if it is already defined to prevent a build issue

In some Windows Embedded 7 SDKs near is still defined, so we need to
undefine it in those cases.

Task-number: QTBUG-32571

Change-Id: I0d48b9dafa2af31f88f48746bfcf4df9fe824554
Reviewed-by: Lorn Potter <lorn.potter@jollamobile.com>