Comment 10 for bug 225055

Well you could see the keyboard rules in /etc/X11/xkb/rules/xorg.lst file for the layouts, variants and options

This variant can be used for "us" layouts

 euro us: With EuroSign on 5
 intl us: International (with dead keys)
 alt-intl us: Alternative international (former us_intl)
 colemak us: Colemak
 dvorak us: Dvorak
 dvorak-intl us: Dvorak international
 dvorak-l us: Left handed Dvorak
 dvorak-r us: Right handed Dvorak
 dvorak-classic us: Classic Dvorak
 rus us: Russian phonetic
 mac us: Macintosh
 altgr-intl us: International (AltGr dead keys)
 olpc2 us: Group toggle on multiply/divide key

i.e if you want U.S. International (with dead keys) you may use

Section "InputDevice"
 Identifier "Generic Keyboard"
 Driver "kbd"
 Option "CoreKeyboard"
 Option "XkbRules" "xorg"
 Option "XkbModel" "pc105"
 Option "XkbLayout" "us"
 Option "XkbVariant" "intl"
EndSection

just add the correct variant into your xorg.conf according the /etc/X11/xkb/rules/xorg.lst rules.