link errors building extensions for Postgres on Windows using MinGW

I'm trying to port an extension that previously ran under Postgres on linux
so that it runs under PostgreSQL 8.0.3 on Windows. I'm using MingGW for the
compiling/linking.

I'm getting problems when I try to link though. Symbols that are defined in
the Postgres server and referenced in my extension cause link errors that
prevent a dll from being produced.
fe-giefToGrid.c:25: undefined reference to `pg_detoast_datum'

fe-udr.c:510: undefined reference to `Float8GetDatum'

libgridfrontendDEBUG.a(fe-udr.o)(.text+0xbe7):fe-udr.c:515: undefined
reference to `get_typlenbyvalalign'

I can get rid of these link errors by linking in the libpostgres.a file
at the cost of a much larger shared library. In theory, I shouldn't need to
though (at least I don't under linux), and doing so may result in two
inconsistent copies of some Postgres internal data structures presumably.
My link line looks like:

gcc -u_etext -shared -fpic -Wl,--whole-archive -o destDir/Grid.dll
-Lmylibdir -L/lib -L/c/Program\ Files/PostgreSQL/8.0/lib -lmylibs
-Wl,--no-whole-archive -lpostgres -lwsock32 -lm 2> link.errs

can anyone suggest a solution?

Thank you,

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Eric Davies, M.Sc.
Barrodale Computing Services Ltd.
Tel: (250) 472-4372 Fax: (250) 472-4373
Web: http://www.barrodale.com
Email: eric(at)barrodale(dot)com
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