> Did you install the “avr-toolchain” package or just the “avr-gcc”?
I have installed the package "avr-toolchain". The program "avr-gcc" is in my profile but I think it was not from the package avr-gcc. $ ls -l /home/dannym/.guix-profile/bin/avr-gcc lrwxrwxrwx 143 root guixbuild 69 1. Jan 1970 /home/dannym/.guix-profile/bin/avr-gcc -> /gnu/store/lhy6jlpwf92yknmfai3675lmr8bhc4jf-avr-gcc-5.3.0/bin/avr-gcc $ guix package -r avr-gcc nothing to be done $ ls -l /home/dannym/.guix-profile/bin/avr-gcc lrwxrwxrwx 143 root guixbuild 69 1. Jan 1970 /home/dannym/.guix-profile/bin/avr-gcc -> /gnu/store/lhy6jlpwf92yknmfai3675lmr8bhc4jf-avr-gcc-5.3.0/bin/avr-gcc I've read through the mailing list but even the "-D__x86_64__" hack doesn't work anymore. Hmm... > Should application setup for individual applications also be added to the > manual? In general yes - but I think avr-gcc is special in that it really doesn't need host system stuff at all. There should be no configuration necessary. (It is necessary, but it shouldn't be) Also, I manually added avr/include and avr/lib as a workaround. This mostly works. However, when linking I get: ... avr-ld: cannot find crtatmega32u4.o: No such file or directory avr-ld: cannot find -latmega32u4 And indeed this crt doesn't exist at all.