that holds flags to be passed in to tgetpass(). Change echo_off
param to tgetpass() into a flags field. There are currently 2
possible flags for tgetpass(): TGP_ECHO and TGP_STDIN. In tgetpass(),
abstract the echo set/clear via macros and if (flags & TGP_ECHO)
but echo is not set on the terminal, but sure to set it.