qt5script-5.1.1 fails to build on MIPS64

../3rdparty/javascriptcore/JavaScriptCore/runtime/JSValue.h: In constructor 'QTJSC::JSValue::JSValue(QTJSC::JSCell*)':
../3rdparty/javascriptcore/JavaScriptCore/runtime/JSValue.h:494:57: error: cast from 'QTJSC::JSCell*' to 'int32_t

{aka int}' loses precision [-fpermissive]
../3rdparty/javascriptcore/JavaScriptCore/runtime/JSValue.h: In constructor 'QTJSC::JSValue::JSValue(const QTJSC::JSCell*)':
../3rdparty/javascriptcore/JavaScriptCore/runtime/JSValue.h:506:78: error: cast from 'QTJSC::JSCell*' to 'int32_t {aka int}

' loses precision [-fpermissive]

Same problem on qt-4.8.5 (https://bugreports.qt-project.org/browse/QTBUG-35030), and we can use the same solution.

The attached patch adds support for MIPS64 and (apparently) fixes the problem, and is based on this patch for webkit-gtk: http://patches.openembedded.org/patch/51625/