It seems that commit ad589ae1685225c96fce05292e2304f4b0afc265 on October 20th broke laplace() for situations requiring the use of the hackit function in laplac.lisp. The commit involves changing the scope of the variable parm.
There were actually two problems. The first was the hackit no longer had access to parm, so this happened:
Maxima encountered a Lisp error:
HACKIT: variable PARM has no value
Then it turned out that the call to mydefint in lapexpt wasn't passing the correct number of arguments (which changed along with parm).
I've attached a patch fixing this issue for me. This makes hackit take a parm parameter and fixes the call to mydefint (notice that this particular call now passes parm for the parm parameter as well as passing parm for the limit of integration--I think this is consistent). This patch also removes a now-superfluous let binding of parm in hackit. Now:
(%o1) --- - atan(s)
[That's pi/2-atan(s) in case the alignment messes up]
I didn't notice any other problems with laplace(). Let me know what you think!