Add implmentation for fwide posix function.
This function is used to set the orientation of a stream to either byte-oriented or wchar-oriented. More info on this function is here: https://man7.org/linux/man-pages/man3/fwide.3p.html This implementation only impmlemnts the manual switching and does not yet guard against using a byte-oriented stream with wchar functions and vice versa. Those step will come in additional commits. Signed-off-by: Wren Turkal <email@example.com>