This reverts commit 6ff886e539 because it
doesn't work when chroot builds are enabled (nix.useChroot = true):
$ nix-build -A arduino
these derivations will be built:
/nix/store/xjv1j3mww4jx1vccfc0p1inlcrlgx2if-arduino-1.6.6.drv
building path(s) ‘/nix/store/58sdiphd4pm3811gir0b8j718pgq8zvk-arduino-1.6.6’
...
untar-unzip-download:
[get] Getting: http://downloads.arduino.cc/reference-1.6.6-3.zip
[get] To: /tmp/nix-build-arduino-1.6.6.drv-0/Arduino-1.6.6-src/build/shared/reference-1.6.6-3.zip
[get] Error getting http://downloads.arduino.cc/reference-1.6.6-3.zip to /tmp/nix-build-arduino-1.6.6.drv-0/Arduino-1.6.6-src/build/shared/reference-1.6.6-3.zip
untar-unzip-checksum:
[echo] Testing checksum of "shared/reference-1.6.6-3.zip"
[checksum] Could not find file /tmp/nix-build-arduino-1.6.6.drv-0/Arduino-1.6.6-src/build/shared/reference-1.6.6-3.zip to generate checksum for.
BUILD FAILED
Reasoning: without a revert, the build farm cannot produce binaries and
users that build from source, without chroot, cannot trust that they get
a working result (non-deterministic build, depending on how pure the
arduino builder is).
2d7e4de12e