SDRAM on NIOS2

Hello Everyone, I am trying to implement edge detection on nios2. so I have designed qsys system with nios2cpu-onchipmeory-jtag uart.

when i run my C code for edge detection i got errors like(1) undefined reference to fseek, fopen, fwrite and (2) .rwdata, .bss in not in the region of onchip.

To reduce first errors i did like. bsp editor-setting-common-HAL and unchecked small c library.

Now How can I reduce second errors.

To remove second errors i can use sdram but can anyone tell me how to use sdram for nios2 system ?

Thanks