I use the "mac" variant option for the US QWERTY layout (`setxkbmap us -variant mac`). This functions as a regular US QWERTY layout, but I've access to various "special" characters and latin extended characters (e.g. æåøœ¡), as well as ^'"`~ as dead keys (to create îûéèñũäüö or whatever) via a modifier key (I use alt, but you can set it to whatever).

This allows me to use a single functional keyboard layout to write English, Norwegian _and_ code in.