[Pragma] Added support for GCC unroll/nounroll

GCC 8 introduced these new pragmas to control loop unrolling. We should support them for compatibility reasons and the implementation itself requires few lines of code, since everything needed is already implemented for #pragma unroll/nounroll.

GitOrigin-RevId: 12a1f1d9d7e4f7ce416d0602d18991973986dfb5
3 files changed