[Buildroot] Incorrect configure --target= and --host= when building ncurses 6.1

[William Tambe]

I am adding a new board for which the architecture name is "iron".
While building ncurses, the following command is issued:

./configure --target=iron-buildroot-linux-gnu --host=iron-buildroot-linux-gnu

Which is throwing the error:
checking host system type... Invalid configuration
`iron-buildroot-linux-gnu': machine `iron-buildroot' not recognized

I believe, the configure command should have been:
./configure --target=iron-linux-gnu --host=iron-linux-gnu

Any idea what could be causing the extra "buildroot" in configure
--target= and --host= arguments ?