[Haskell-cafe] Prologue junk? - compiling lambdabot:Plugin.Pl.Transform

[Iain Alexander]

I'm trying to build lambdabot 4.0 with ghc-6.4.1 (gcc (GCC) 3.4.2 (mingw-
special)) and Cabal-1.1.6.1 on WinXP SP2.  I've got as far as 
Plugin.Pl.Transform.hs, and I get

*** Mangler
g:\ghc\ghc-6.4.1\perl g:\ghc\ghc-6.4.1\ghc-asm 
C:\DOCUME~1\IAINAL~1\LOCALS~1\Tem
p\ghc2736.raw_s C:\DOCUME~1\IAINAL~1\LOCALS~1\Temp\ghc2736.s 4
Prologue junk?: _s7f7_ret:
        xorl    %ecx, %ecx
        xorl    %eax, %eax
        movl    %ecx, 8(%esp)
        movl    %eax, 12(%esp)
/APP

Transform.hs uses
{-# OPTIONS -fvia-C -O2 -optc-O3 #-}

I've tried and failed to make sense of why the mangler's failing.  I don't know 
if this is a known problem with 6.4.1 on XP.

I'm not sure what to try next.  I could turn off the aggressive optimisation, 
but I don't know how much that would cost me.  I've got 6.4.2 installed, so I 
could try that, although I'd need to rebuild all the prerequisites.  Anything 
else?
-- 
Iain Alexander      ia at stryx.demon.co.uk