ac_prog_ssh

Check for the program 'ssh', let script continue if exists, pops up error message if not.

Besides checking existence, this macro also set these environment variables upon completion:

     SSH = which ssh

AC_DEFUN([AC_PROG_SSH],[
AC_REQUIRE([AC_EXEEXT])dnl
AC_PATH_PROG(SSH, ssh$EXEEXT, nocommand)
if test "$SSH" = nocommand; then
        AC_MSG_ERROR([ssh not found in $PATH])
fi;dnl
])