@c Change owner of a file
This function implements the chown command of the UNIX operating system on UNIX and Windows NT. The first argument is the ZCHAR terminated file name. No wild card characters are allowed.
The second argument is the name of the desired new user. The function sets the owner of the file to the specified user, and returns zero if the setting was succesful. If the setting fails the function returns an error code. The error codes are:
COMMAND_ERROR_CHOWN_NOT_SUPPORTED COMMAND_ERROR_CHOWN_INVALID_USER COMMAND_ERROR_CHOWN_SET_OWNER
int file_chown(char *pszFile,
char *pszOwner
){