Extcalc

We got this bug report in Debian:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=517963

It seems to me to unnecessarily report an error
when run as a substituted command in bash's shell.

Here's how to duplicate the bug:

$ echo $( concalc 1 + 1 )
tcsetattr fehler: Invalid argument
tcsetattr error: Invalid argument
2

I noticed that it also returns the correct answer,
which in this case is 2.

However, the same command with no substitution
reports no error

$ concalc 1 + 1
2