i'm afraid i can't make a PKGBUILD yet (given that i am pretty new to Archlinux), but i can at least write down all the packages I was asked for on an (almost) fresh Arch install in order to get Trine 2 to work. In addition to the two you mentioned (lib32-libglade and lib32-libxxf86vm) i needed:
lib32-glu
lib32-libogg
lib32-libvorbis
lib32-gtk2
lib32-atk
lib32-pango
lib32-libxinerama
and
lib32-openal
(though i'm not sure this one was the correct one, since audio does not work yet in my Trine 2).
EDIT : after having also installed alsa-thing packages sound also works (lib32-alsa-utils, lib32-alsa-lib, lib32-libpulse, alsa-utils, lib-alsa-oss : i think less was needed but i don't exactly know)
Hope it helps!
]]>but i do not purchase 15$ to create a PKGBUILD
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