Change Details

- change __riscv__ with __riscv - change __riscv64 with (__riscv && __riscv_xlen == 64) this is required to support new GCC 7.1 compiler

``` - change __riscv__ with __riscv - change __riscv64 with (__riscv && __riscv_xlen == 64) ``` this is required to support new GCC 7.1 compiler

``` - change __riscv__ with __riscv - change __riscv64 with (__riscv && __riscv_xlen == 64) ``` this is required to support new GCC 7.1 compiler