Add linux/kd.h to the config test for evdev

This header is used by qevdevmousehandler.cpp, so it's not a bad idea
to check that it exists as early as here. Apparently, FreeBSD's Linux
support has linux/input.h, so the "evdev" test was passing and then
the build would fail later.

Task-number: QTBUG-36205
Change-Id: Iab9788350a9f4c90d355524769a7a396679fd218
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@digia.com>
Make QCommandLineParser not crash if passed a bad QCommandLineOption

This otherwise crashed:
  QCommandLineOotion opt("with=equals");
  parser.isSet(opt);

Can't write a unit test because it produces a warning.

Change-Id: Ifc67f20bb4b16b96d93dffbe4e82e6cc8a17584d
Reviewed-by: David Faure <david.faure@kdab.com>