Error while compiling c++ program for riscv target on llvm

We are trying to compile a c++ program for riscv target on qemu simulator by using following command.
/riscv-build/bin/clang++ --target=riscv64 -march=rv64gc hello.cpp -o hello --rtlib=compiler-rt -stdlib=libc++ -lc++ -lc++abi -lunwind --sysroot=/riscv-build -v -std=c++14
The clang++ was generated through cross compilation using riscv toolchain with a host machine running on X86 architecture and ubuntu 20.04, the target is a qemu simulator with linux operating system simulated for riscv
Using this command gave us the following error:
In file included from hello.cpp:1:
In file included from /riscv-build/include/c++/v1/iostream:37:
In file included from /riscv-build/include/c++/v1/ios:214:
In file included from /riscv-build/include/c++/v1/iosfwd:95:
/riscv-build/include/c++/v1/wchar.h:119:15: fatal error: ‘wchar.h’ file not found
#include_next <wchar.h>
^~~~~~~~~
1 error generated.
as per our understanding, #include_next should look for wchar.h in a sub directory under /riscv-build/include/c++/v1 but there does not seem to be another wchar.h present.