I configured darcs stable (1.0.5) with --enable-git, and the linker aborts with 
many messages like

ld: multiple definitions of symbol ___stginit_Git_
Git.o definition of ___stginit_Git_ in section (__TEXT,__text)
git.o definition of ___stginit_Git_ in section (__TEXT,__text)

I notice that there are source files Git.lsh and git.c.  I also notice that my 
file system is case independent, which would map the corresponding object files 
Git.o and git.o to the same file.  This may cause this problem.

On Thu, Dec 22, 2005 at 11:44:08AM +0000, Erik Schnetter wrote:
> ld: multiple definitions of symbol ___stginit_Git_
> Git.o definition of ___stginit_Git_ in section (__TEXT,__text)
> git.o definition of ___stginit_Git_ in section (__TEXT,__text)
> 
> I notice that there are source files Git.lsh and git.c.  I also notice
> that my file system is case independent, which would map the
> corresponding object files Git.o and git.o to the same file.  This may
> cause this problem.

Sounds like a correct analysis to me.  So the solution presumably would be
to rename either git.c or Git.lhs (probably git.c) so they don't produce
object files having the same name (apart from case).
-- 
David Roundy
http://www.darcs.net

This particular issue has been fixed in the unstable branch; however, it has not
been confirmed whether Darcs-Git now works on Darwin.

Feel free to reopen this bug if you find it doesn't.

fixed in 1.0.6
Thu Dec 22 12:53:18 CET 2005  Erik Schnetter <schnetter@cct.lsu.edu>
  * Rename git.c to gitlib.c