patch from about a year ago (I couldn't use any code of his yet, though,
but there are a few things left). The emergency keys are triggered by
pressing Alt-SysReq + key.
* By default, only Alt-SysReq+'d' is used as a means to deliberately enter
the kernel debugger. F12 belongs to userland again, now :-)
* Debugger add-ons now have another optional method to implement their own
emergency keys - 'd' for the debugger cannot be overridden, though.
* The mechanism can be turned off via a new kernel setting, so it's not that
easy anymore to "crash" Haiku if you don't want to.
* Right now, the PS/2 driver, and the pre-input_server in-kernel debugger
keyboard mini-driver support this, USB not yet.
* Minor cleanup.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@31660 a95241bf-73f2-0310-859d-f6bbb57e9c96
c755ecfe96