Koromix [1] filed a deletion request for arduino-toolchain [2]: This package was used to provide the upstream compiler toolchain for my arduino package instead of using Arch Linux's AVR toolchain. I changed things so that arduino now keeps the upstream toolchain and arduino-native uses Arch Linux's one. Bottom line, this package is obsolete and broken. [1] https://aur.archlinux.org/account/Koromix/ [2] https://aur.archlinux.org/pkgbase/arduino-toolchain/