[racket] CGC embedding on win64

Hi,

 I'm following the "Inside: Racket C API" guide, section 1.4.1
"Embedding Racket into a Program" to learn how to embed a racket
interpreter into my program: When I compile the sample code on win64
I'm  getting the following error at link time:

"error LNK2019: unresolved external symbol
__imp_scheme_external_get_thread_local_variables referenced in
function scheme_get_thread_local_variables"

Also, if I try to add the

static __declspec(thread) void *tls_space;
...
scheme_register_tls_space(&tls_space, 0);

code as suggested in the guide I get an "identifier not found error"

*Environment:

OS: Windows 7 64bit

Compiler: VC++ 2008 (64bit)

Racket: git clone, Dec 30, 2010; built by running 'build.bat' from
within the VC++ 64bit shell

Any help will be greatly appreciated.

Ugo