Ninja integration: msvc parser can't read moc errors

When a moc call in a msvc/ninja build fails, the error line couldn't be parsed.

It's not a redirecting problem, also the ninja build passes the line to

bool MsvcParser::processCompileLine(const QString &line)
{
    sendQueuedTask();

    if (m_compileRegExp.indexIn(line) > -1) {

But m_compileRegExp doesn't match.

In a qmake based build the line looks like this:

..\..\..\..\qt-creator\src\plugins\cmakeprojectmanager\cmakeeditor.h(55): Error: Undefined interface

The ninja build prints an absolute path with slashes:

E:/sandbox/creator/loaden/src/libs/utils/iwelcomepage.h(54): Error: Undefined interface