I'm gonna use it with libbacktrace - I'll need the path of the
executable before I can use idStr (and thus before I could call
Sys_GetPath(PATH_EXE, str)).
handling SIGTTIN/OU allows running Doom3 in the background (or even
sending it to the background with Ctrl-Z + bg) by disabling TTY input
(before it would get stuck when run in background without +set in_tty 0,
see #215)
While at it, I also added signal handlers for some common crash signals
(SIGILL, SIGABRT, SIGFPE, SIGSEGV) to print a backtrace before exiting
the game (partly based on Yamagi Quake II code).
Since we don't have our own signal handler anymore, those two
init functions can be merged into the existing Sys_Init(), which
is already called by common->Init().
Don't include the lazy precompiled.h everywhere, only what's
required for the compilation unit.
platform.h needs to be included instead to provide all essential
defines and types.
All includes use the relative path to the neo or the game
specific root.
Move all idlib related includes from idlib/Lib.h to precompiled.h.
precompiled.h still exists for the MFC stuff in tools/.
Add some missing header guards.
Thread return types are different between platforms, and its
probably not a good idea to return something of a different size,
cast the callback and expect it to not crash.
