Fix building Stack on ARM

[borsboom]

Stack now uses store, which does not currently build ARM and some other processors (see mgsloan/store#37). First store will need to be fixed, and then Stack will have to use the new store version.

ping @mgsloan

[mgsloan]

I have a patch for review on store: mgsloan/store#78

Pending someone actually testing it on ARM, and perhaps more code review.

[mgsloan]

I've updated stack to use store-0.3 In theory this is now resolved. Pending test by someone who has an ARM machine - pinging @dysinger

[mitchty]

If you like I can give it a test on my arm port. Is the master branch the thing to test?

[mgsloan]

Yep it'd be the master branch. Crossing my fingers that it works!

[borsboom]

@mgsloan: I've tested the master branch of store on armv7 (only took 20 hours to build using qemu) and get the following test failures:

      test/Data/Store/StreamingSpec.hs:52:
      1) Data.Store.Streaming.decodeMessage.ByteString Throws an Exception on messages that are shorter than indicated.
           uncaught exception: PokeException (PokeException {pokeExByteIndex = 4, pokeExMessage = "encode undershot end of 8 byte long buffer"})

      test/Data/Store/StreamingSpec.hs:53:
      2) Data.Store.Streaming.decodeMessage.ByteString Throws an Exception on messages that are longer than indicated.
           uncaught exception: PokeException (PokeException {pokeExByteIndex = 16, pokeExMessage = "encode undershot end of 20 byte long buffer"})

Full log is at https://gist.github.com/borsboom/7bd922f62e62c42f4aaa3c5f4e24cad6.

[mgsloan]

I believe those failures are due to the tests assuming that the size of Int is 64 bits. So happily, I think unaligned access is working fine. If you still have that emulator handy, I've pushed a commit disabling those tests.

[borsboom]

The tests now pass, and stack passes its tests when built against this version of store.

[mgsloan]

Woohoo! I think we can consider this resolved.

[mitchty]

Yep, I managed to get it to build, forgot to post that bit (had some build issues that were just no swap space due to a reboot):

# file ./.stack-work/install/arm-linux/lts-7.0/8.0.1/bin/stack
./.stack-work/install/arm-linux/lts-7.0/8.0.1/bin/stack: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-musl-armhf.so.1, stripped
# ./.stack-work/install/arm-linux/lts-7.0/8.0.1/bin/stack --version | head -n 3
Version 1.2.1, Git revision 89c699b4083953406336647c52b42acbf48beac2 (dirty) (4308 commits) arm
Compiled with:

[borsboom]

stack-1.3.0 ARM binary is now uploaded to the release: https://github.com/commercialhaskell/stack/releases/download/v1.3.0/stack-1.3.0-linux-arm.tar.gz