QProcess: Make it possible to set native process creating flags

Please make it possible to pass native process creating flags when creating a process with the QProcess class.

Something like QProcess::setNativeCreationFlags(), which of course would be platform-specific, would be extremely helpful.

In particular, in our project we need to pass the CREATE_BREAKAWAY_FROM_JOB creating flag on the Win32 platform.

This flags is required, because Windows (Vista and later) automatically adds the child process to a PCA (Program Compatibility Assistant) job object.

As a consequence, the process can NOT be added to our own job object anymore - on Win32 processes can be assigned to exactly one job object.

And once it has been assigned to a job object (e.g. the PCA job object), a process can NOT be assigend to another job object anymore. AssignProcessToJobObject() will simply fail

Only by using the CREATE_BREAKAWAY_FROM_JOB flag in CreateProcess(), we can avoid getting added to the PCA job object and correct functionality of AssignProcessToJobObject() is restored.

For details please read here:
http://blogs.msdn.com/b/cjacks/archive/2009/07/10/how-to-work-around-program-compatibility-assistant-pca-jobobjects-interfering-with-your-jobobjects.aspx

In addition to being able to set the CREATE_BREAKAWAY_FROM_JOB flag, it would also be great to be able to set CREATE_SUSPENDED when needed.

Normally, on Win32, we would create a process with CREATE_SUSPENDED, add the new (but suspended) process to our job object and then resume the process.

QProcess does not currently allow us to create a process in suspended state at all

So please consider adding QProcess::setNativeCreationFlags() in a future version. Until then, we have to patch Qt for our requirements.

We are pretty sure that this will be very helpful for other developers too...