This a patch for https://aur.archlinux.org/packages/lib32-gtkglext/ to fix the compile error arond the use of the variable name 'index'.
To apply, clone the repo and apply git git patch before building:
git clone https://aur.archlinux.org/lib32-gtkglext.git
cd lib32-gtkglext
curl -LO https://gist.github.com/jonjonw/39031796ca230e240311fbb73085bd80/raw/lib32-gtkglext.git.diff
git apply lib32-gtkglext.git.diff
makepkg -si