Install libn32stdc++-7-dev-mips64el-cross by entering the following commands in the terminal:
sudo apt update sudo apt install libn32stdc++-7-dev-mips64el-cross
GNU Standard C++ Library v3 (development files) (mips64el)
This package contains the headers and static library files necessary for building C++ programs which use libstdc++. . libstdc++-v3 is a complete rewrite from the previous libstdc++-v2, which was included up to g++-2.95. The first version of libstdc++-v3 appeared in g++-3.0. . This package contains files for mips64el architecture, for use in cross-compile environment.