Build problem

I tried to add some code to src\vm, and call it in src\fjit, but
ran into linking problem. Here is what I did.

In inc\corjit.h, I added:

  int foo(int x);

In vm\jitinterface.cpp, I added:

  int foo(int x) { return x; }

In fjit\fjit.cpp, I added a call foo(3) in the method
FJit::compileCEE_LDFLD.

To build, I typed "build" in the src folder, but got the following
linking error:

Linking Executable - c:\yuan\proj\rotor\sscli\clr\bin\rotor_x86
\checked\mscorejt.dll for i386
fjit.obj : error LNK2019: unresolved external symbol "int
__stdcall foo(int)" (?foo@@YGHH@Z) referenced in function "private: enum
FJitResult __thiscall FJit::compileCEE_LDFLD(enum
opcode_t)" (?compileCEE_LDFLD@FJit@@AAE?
AW4FJitResult@@W4opcode_t@@@Z)

What was wrong with this?  Help is greatly appreciated!

-Yuan