On SunOS leo 5.10 Generic_137111-02 sun4u sparc SUNW,Sun-Fire-280R
I've created a darcs binary
http://www.informatik.uni-bremen.de/agbkb/forschung/formal_methods/CoFI/hets/solaris/ghcs/darcs
without libcurl from the sources of darcs-2.1.0pre2

I haven't tested it much. So try if it works for you.