TMS320C6678: Mathlib Link Problem

I'm getting a link error that I can't figure out.

My code is:

/**
* main.c
*/
#include <ti/mathlib/mathlib.h>
int main(void)
{
float a=3.0f,b;
b = cossp(a);
return 0;
}

I get:

undefined first referenced
symbol in file
--------- ----------------
cossp ./main.obj

error #10234-D: unresolved symbols remain
error #10010: errors encountered during linking; "mtest.out" not built