When cross-debugging on a target that uses a debugging stub or external 
simulator that speaks GDB remote protocol, we'd like to have Eclipse 
automatically launch the stub, as well as GDB, when the user clicks on the 
"Debug" button.  Unfortunately, there's a race condition here: GDB may try to 
open the TCP port to the stub before the stub has finished its own 
initialization and started listening for a connection, which leaves GDB with a 
"connection refused" error and the stub stuck waiting for a connection that 
never arrives.

The attached patch addresses this by adding an auto-retry feature to "target 
remote" TCP connections, and extending the existing timeout logic to cover 
polling for retry attempts as well as waiting for connections that are merely 
slow.  I've done a fair amount of manual testing with this in both Linux and 
Mingw32 host builds and it seems to DTRT reliably.

Does this look OK?  I'm not really wedded to the details here, if others want to 
argue for different command names, different timeout handling, etc.

-Sandra