On running command scons ./build/RISCV/gem5.debug i get following compilation error!

build/RISCV/arch/riscv/linux/process.cc:671:44: error: no matching function for call to 'SyscallDesc::SyscallDesc(const char [7], )'
{215, SyscallDesc("munmap", munmapFunc)},
^
In file included from build/RISCV/arch/riscv/linux/process.cc:48:0:
build/RISCV/sim/syscall_desc.hh:74:5: note: candidate: SyscallDesc::SyscallDesc(const char*, SyscallDesc::SyscallExecutor)
SyscallDesc(const char name, SyscallExecutor sys_exec=unimplementedFunc)
^~~~~~~~~~~
build/RISCV/sim/syscall_desc.hh:74:5: note: no known conversion for argument 2 from '' to 'SyscallDesc::SyscallExecutor {aka std::function<SyscallReturn(SyscallDesc, int, ThreadContext*)>}'
build/RISCV/sim/syscall_desc.hh:69:7: note: candidate: SyscallDesc::SyscallDesc(const SyscallDesc&)
class SyscallDesc {
^~~~~~~~~~~
build/RISCV/sim/syscall_desc.hh:69:7: note: candidate expects 1 argument, 2 provided
build/RISCV/sim/syscall_desc.hh:69:7: note: candidate: SyscallDesc::SyscallDesc(SyscallDesc&&)
build/RISCV/sim/syscall_desc.hh:69:7: note: candidate expects 1 argument, 2 provided