Bug in placing _stub.o files with HEAD

[Einar Karttunen]

Hello

I noticed the following behaviour using GHC 6.5.20050728:
If compiling a Cabal package containing hs-source-dirs it 
places the _stub.o under dist/build/<source-dir>/path/to/Module
when Cabal expects it in dist/build/path/to/Module. Things
appear to work without hs-source-dirs. 

For example with "hs-source-dirs: src"
Network/GnuTLS/IOWrap.hs contains foreign export declarations.
runnning Setup build creates the files:
dist/build/src/Network/GnuTLS/IOWrap_stub.o
src/Network/GnuTLS/IOWrap_stub.h
src/Network/GnuTLS/IOWrap_stub.c

But Cabal fails to include the IOWrap_stub.o as it is 
expected as dist/build/Network/GnuTLS/IOWrap_stub.o

- Einar Karttunen