Compiling ruby.h with precompiled headers

[Geo Tavros]

Hi,
I'm trying to use Ruby in my C++ project. My project uses precompiled
headers, but when I try to include ruby.h header in it I get errors in
win32.h files that lie in RUBY_INCLUDE folder. Here is error:
...ruby\lib\ruby\1.8\i386-mswin32\win32\win32.h(172) : error C2061:
syntax error : identifier 'fd_set'
ruby\lib\ruby\1.8\i386-mswin32\win32\win32.h(188) : error C2146: syntax
error : missing ';' before identifier 'rb_w32_get_osfhandle'
ruby\lib\ruby\1.8\i386-mswin32\win32\win32.h(188) : fatal error C1004:
unexpected end of file found

Is there any way to avoid such error?
P.S. I'm using MSVC 6, Windows 7 OS
I've tried to create a project without precompiled header and it worked
fine.