XCB: Print error code on Xlib I/O errors

When Xlib detects that its underlying XCB connection got into an error
state, it calls its I/O error handler. However, the default
implementation doesn't print the error code from XCB which might be
useful for debugging.

This commit adds an I/O error handler which prints the error code from
XCB with a string describing the error and then calls Xlib's default
error handler.

Change-Id: I7f1fb3f1e8d0fdc3ac9db03ae7d154330c31db0c
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
Cocoa: Set the COCOA_MENU_ANCESTOR() also when sync'ing

Task-number: QTBUG-38044

Change-Id: I2769bf2f4beec058c15ba1d126e59106f41dab37
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
Cocoa: Send expose event on screen change.

Required to repaint OpenGL content properly.

Task-number: QTBUG-38105
Change-Id: Ie9441d56bd9d1a4eb399210369592f03e19c4929
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>