Prevent cross-talk between different Qt builds on OS X.
Prevent cross-talk between different Qt builds on OS X.

/Library/Frameworks/ is hardcoded as a .prl file lookup path, which
sometimes wreaks havoc when depot builds pick up settings and binaries
from an installed binary package.

Remove /Library/Frameworks from the qmake sources. The binary package
build script already adds -F /Library/Frameworks explicitly.

/Library/Frameworks is still kept as a default _framework_ search path,
since it does not seem to cause trouble, and people may be relying on
that path being searched by default.

igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,radekp/qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,radekp/qt,radekp/qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,radekp/qt,radekp/qt,pruiz/wkhtmltopdf-qt,radekp/qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,radekp/qt,pruiz/wkhtmltopdf-qt,radekp/qt,radekp/qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,radekp/qt,igor-sfdc/qt-wk