Add wcswidth and test

src/header/wchar/mod.rs

tests/Makefile

tests/expected/bins_dynamic/args.stdout

tests/expected/bins_dynamic/errno.stderr

tests/expected/bins_dynamic/errno.stdout

tests/expected/bins_static/alloca.stderr

tests/expected/bins_static/alloca.stdout

tests/expected/bins_static/arpainet.stderr

tests/expected/bins_static/arpainet.stdout

tests/expected/bins_static/assert.stderr

tests/expected/bins_static/assert.stdout

tests/expected/bins_static/constructor.stderr

tests/expected/bins_static/constructor.stdout

tests/expected/bins_static/ctype.stderr

tests/expected/bins_static/ctype.stdout

tests/expected/bins_static/destructor.stderr

tests/expected/bins_static/destructor.stdout

tests/expected/bins_static/dirent/scandir.stderr

tests/expected/bins_static/dirent/scandir.stdout

tests/expected/bins_static/error.stderr