Error riscv-isa-sim 'runtime_error' not a member of 'std'

I tried to install RISCV toolchain in ubuntu 20.10. I got error

Configuring project riscv-isa-sim
Building project riscv-isa-sim

./fesvr/ In member function ‘uint32_t dtm_t::get_xlen()’:
…/fesvr/ error: ‘runtime_error’ is not a member of ‘std’
488 | throw std::runtime_error(“FESVR DTM Does not support 128-bit”);
| ^~~~~~~~~~~~~
…/fesvr/ error: ‘runtime_error’ is not a member of ‘std’
505 | throw std::runtime_error(“FESVR DTM can’t determine XLEN. Aborting”);
| ^~~~~~~~~~~~~
…/fesvr/ warning: control reaches end of non-void function [-Wreturn-type]
506 | }
| ^
Can you help me on this.

This doesn’t have anything to do with the HiFive Unmatched. And doesn’t appear to have anything to do with SiFive either. I would suggest filing an issue in the riscv-isa-sim github tree asking for help.

This was also reported as an issue in riscv-tools github. I will answer it there.