nested sha1

[d2]

Hey guys, I have a function for generating hashes and it looks like that:

Code:

sha1($salt.sha1($str))

Is there a clever way of telling hashcat to crack such combination?

EDIT: the obvious one would be to perform sha1($str) first, but with big dictionaries it can take ages (or is there any good gpu-based software which can speed up whole process?)