test for curses before bootstrap

[Adam Hoka <adam.hoka%gmail.com@localhost>]

Wouldn't it be a good idea to include a check for curses headers during 
bootstrap?
I know its RTFM, but it may be non-trivial to track down why the bootstrap 
stoped.

Something like this:

  echo_msg "Looking for curses header files"
  if [ ! -f /usr/include/curses.h ] || [ ! -f /usr/include/ncurses.h ]; then
          die "You need curses header files to bootsrap pkgsrc (see 
README.$opsys)"
  fi

Cheers, 
 Adam Hoka