Building a project(JPEG Encoder) in Nios II SBT.

When I build a project(JPEG Encoder) in Nios II SBT, it doesn't create .elf file. There is no any error, but it gives a warning message.

Here is the message:

c:/altera/15.0/nios2eds/bin/gnu/h-x86_64-mingw32/bin/../lib/gcc/nios2-elf/4.9.1/../../../../../H-x86_64-mingw32/nios2-elf/lib\libc.a(lib_a-unlinkr.o): In function `_unlink_r':

/build/arc/temp/123844302/ACDS_lwr/ip/sopc/app/gnu/BUILD/gnu/build-newlib.nios2-elf.x86_64-w64-mingw32/nios2-elf/newlib/libc/reent/../../../../../src/newlib-1.18/newlib/libc/reent/unlinkr.c:54: warning: warning: unlink is not implemented and will always fail

Can anyone help with this?