Position independent code (?)

Hi, I'm trying to compile a program on x86_64, but when it gets to the final linking stage, I get the error relocation R_X86_64_PC32 against `prefetch_C_withmask' can not be used when making a shared object; recompile with -fPIC I've tried putting -fPIC every place I can find where it is legal to do so, but I still always get the same error Does anyone know what this relocation is, and why I keep getting the error?