Can't find libstdc++
Install lib32std+cc

Add the path to firefox to /etc/ld.so.conf.d/libc.conf
/opt/firefox

Can't open libXrender
install ia32-libs

I installed libdesktop-agnotic0-gio aswell.

I also got a heap of errors regarding "wrong ELF class: ELFCLASS64"
Run this command in the terminal before
export GTK_PATH=/usr/lib32/gtk-2.0