Takusen build error

[Benjamin Franksen]

I get a strange error building Takusen (more precisely: the module
Foreign/C/UTF8.hs) with ghc-6.8.3. It says

aragon: .../ghc-6.8.3/Takusen-0.8.1 > ./Setup build -v
Reading parameters
from /srv/projects/ctl/franksen/haskell/ghc-6.8.3/Takusen-0.8.1/takusen.buildinfo
Creating dist/build (and its parents)
Creating dist/build/autogen (and its parents)
Preprocessing library Takusen-0.8.1...
Building Takusen-0.8.1...
Building library...
Creating dist/build (and its parents)
Creating dist/build (and its parents)
/projects/ctl/franksen/usr/bin/ghc -package-name
Takusen-0.8.1 --make -hide-all-packages -i -idist/build/autogen -idist/build -i. -Idist/build -I/opt/oracle/product/client/rdbms/demo -odir
dist/build -hidir dist/build -stubdir dist/build -package
base-3.0.2.0 -package mtl-1.1.0.1 -package time-1.1.2.1 -package
old-time-1.0.0.0 -O -XCPP Database.Enumerator Database.Util
Database.Oracle.Enumerator Database.Oracle.OCIConstants
Database.Oracle.OCIFunctions Database.Stub.Enumerator
Control.Exception.MonadIO Foreign.C.UTF8 Database.InternalEnumerator
[1 of 9] Compiling Foreign.C.UTF8   ( Foreign/C/UTF8.hs,
dist/build/Foreign/C/UTF8.o )
/tmp/ghc18936_0/ghc18936_0.s: Assembler messages:

/tmp/ghc18936_0/ghc18936_0.s:1257:0:
     Error: symbol `base_GHCziBase_Z0T_closure' is already defined


I compiled ghc-6.8.3 from source, using ghc-6.8.2 to bootstrap.

Any ideas?

Cheers
Ben