EWARM linker function redefinition problem

In one 'c' file I define the following function:

void fnTemp(int jj, int kk);

void fnTemp(int jj, int kk)

{

     ...do some stuff...

}

In a different 'c' file I have the following:

extern void fnTemp(int jj);

void fnTryIt(void)

{

    fnTemp(3);

}

This will link without any errors. How do I get the linker to tell me that I have two definitions for fnTemp()?

I know that I could put the declaration for fnTemp() in a .h file and include the .h file in both .c files which will then trigger a compiler error. But I have an instance where that can cause other issues.

Thank you for any help.