This patch adds a new config option to qmake to enable full optimization
where it makes sense. This currently is supported on all gcc like
compilers by exchanging -O2 for -O3.
In qtbase it is used to enable full optimizations on qtcore and qtgui
and in a later patch can be used to replace similar existing logic in
QtWebKit's WTF and JavaScriptCore modules.
This fixes a performance regression from gcc 4.7 to 4.8 in the software
renderer.
An aliasing error in qregion.cpp which was exposed by more aggresive
optimization has been solved as well.
Change-Id: Ic2c6c41b79cb3846212b40e7bcc11ff492beb27f
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
cd652500af