[Qt] Add top-level .qmake.conf

[Qt] Add top-level .qmake.conf

With Qt5, this makes setting $QMAKEPATH externally unnecessary.

The magic in the perl scripts to set QMAKEPATH is still there, as it doesn't
hurt, and is still required for Qt4.

https://bugs.webkit.org/show_bug.cgi?id=90461

Patch by Oswald Buddenhagen <oswald.buddenhagen@nokia.com> on 2012-07-06
Reviewed by Tor Arne Vestbø.

.:

* .qmake.conf: Added.
* WebKit.pro:

Tools:

* qmake/mkspecs/features/default_pre.prf:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@121964 268f45cc-cd09-0410-ab3c-d52691b4dbfc