Fix 'sed: RE error: illegal byte sequence' (#1714)
Fix 'sed: RE error: illegal byte sequence' (#1714)

... by unsetting `LC_ALL` and passing `LC_CTYPE=C` to `sed`.

This commit fixes issue #1454.
pyenv/pyenv,yyuu/pyenv,yyuu/pyenv,sebhahn/pyenv,pyenv/pyenv,sebhahn/pyenv,sebhahn/pyenv,pyenv/pyenv