Terminal broken with calc as backend and undefined input

[jarun]

Steps to repro on Ubuntu:

• Install apcalc on Ubuntu
• Run the following

$ export BCAL_USE_CALC=1
$ bcal -b
q/double Enter -> quit, ? -> help
calc> qq
"qq" is undefined

calc>

Terminal gets broken ( need to type twice to show a character). Happens with any invalid command.

Note: bc works. Probably calc prints additional blank newline (the blank line) but bcal quits after reading the first line "qq" is undefined.