dbghelp: Return TRUE in SymInitializeW if process is already initialized and add an ERR to SymCleanup.

Remove an extra fpu context save left over from testing.

winex11.drv: Moved initialization of screen_width/height to xinerama_init to do it inside the x11 lock.

winex11.drv: Don't create a win_data structure for the desktop window, except in the process that owns it.

Handle desktop size changes by sending a message to the desktop owner.

rpcrt4: Only initialise the context handle to NULL in NdrContextHandleUnmarshall if it is an out-only or return one.

Fix the indentation and add tracing of the context handle flags.