Changed the code to bring back assertion popups for everyone, but turn
off assertions around the _get_osfhandle() call in allocate_sfd(). The
original port code was designed knowing that some of the passed
parameters would be invalid, but was expecting that the call would just
fail instead of generating an assert dialog. Turning off Asserts around
this call results in behavior similar to mingw.
Also, turn off Incremental Linking for ssh.exe since half the time, the
linker would trap on this project.
The sfds code blindly uses _get_osfhandle on values that may be file
descriptors, sockets or io handles. Under visual studio, _get_osfhandle
will call the invalid parameter handler for items that are not file
descriptors. Adding the handler allows us to call this in the same way
that mingw does. We will still get an assertion, but a prior change
sends those to stdiout instead of making the user click through a
dialog.
pty and tty support was not enabled or working in the code. Without pty
support, ssh client was very non functional - e.g. openssh linux server
prompt would not come through. Now ssh client works much better in
interactive mode ( uses pty).
