CCS/EK-TM4C1294XL: Linking external functions and variables?

Part Number: EK-TM4C1294XL

Tool/software: Code Composer Studio

In my application I have the main.c file, and the I have a file, Codes.c.

Codes.c contains a lot of bit patterns and then:

static volatile char tempcode [16384];
static volatile int CodeLength;
static volatile int CodeIdx;

void BuildCode(int CL) {

int i;

  CodeLength=CL;

  tempcode[..]= bla.bla;
  ..
  ..
}

In main.c I have the following:

//Links to Codes.c
extern void BuildCode(int CL);
extern char tempcode [16384];
extern int CodeLength, CodeIdx;


..
..

void CGsetupISR(void)
{
    unsigned short NextData;
    //Clr interrupt
    GPIOIntClear(GPIO_PORTQ_BASE, GPIO_PIN_2);

    //Clr DC
    GPIOPinWrite(GPIO_PORTQ_BASE,GPIO_PIN_0, 0);

    if (CodeLoad==1)
    {
        CodeIdx++;
        if (CodeIdx>CodeLength)
        {
            CodeLoad=2;
            return;
        }
    }
    else
    {
      ..
      ..
    }

    if (CodeLoad=1)
        NextData=tempcode[CodeIdx];
    else
        ..

}

void UploadCode(int len) {
    BuildCode(len);  //Load code into buffer and copy 7 times

    CodeLoad=1;
    CodeIdx=0;

    SendFirstCGData();

}

This all compiles fine, but entering the link phase, I get:

 undefined       first referenced
  symbol             in file     
 ---------       ----------------
 CodeIdx         ./main.obj      
 CodeLength      ./main.obj      
 tempcode        ./main.obj      

I have tried:

#include "Codes.c"

.. but then I get:

error #10056: symbol "BuildCode" redefined: first defined in "./Codes.obj"; redefined in "./main.obj"

This comes with or without commenting out the external ref. to that function.

How do I solve this?

PS. I have tried to edit typos, obvious wrong format in the code parts etc, but this editor really do not want you to edit anything?