llvm-{5,6}: unconditionally set triples

[dtzWill]

Previously we only set these when using musl.

See #42452 (comment)

Same should be done for changes in #42452,
I'll add a follow-up commit doing so in the PR containing this
or wherever makes sense-- depending on how review/merging of that goes.

Sending to staging since these later LLVM versions are used in many
places, in particular are the basis of Darwin stdenv :).

Building/testing still underway, help appreciated since this is fairly
wide-reaching and I can only test so much (and can't test Darwin at all).

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Fits CONTRIBUTING.md.

---

[Ericson2314]

I guess slight addendum is I think llvm4 is fine for master, so maybe worth it doing separately? I hate saying things like that, but our newly-worse staging logjams (a good sign of progress, really!) make that more compelling.

[dtzWill]

Sure! I'm more concerned about this being "right" in various scenarios I may not have tried/thought of/etc. :).

I'll split off a PR for just LLVM 4 and reduce this to 5/6, coming soon... :)

[dtzWill]

@GrahamcOfBorg build tests.cc-wrapper-clang-5 tests.cc-wrapper-libcxx-5
@GrahamcOfBorg build tests.cc-wrapper-clang-6 tests.cc-wrapper-libcxx-6

[GrahamcOfBorg]

Success on x86_64-linux (full log)

Attempted: tests.cc-wrapper-clang-5, tests.cc-wrapper-libcxx-5

Partial log (click to expand)

checking whether compiler builds valid C++ binaries... ok
checking whether compiler uses NIX_CFLAGS_COMPILE... ok
checking whether compiler builds valid C++ binaries... ok
checking whether compiler uses NIX_LDFLAGS... ok
checking whether compiler uses NIX_CFLAGS_COMPILE... ok
checking whether sanitizers are fully functional... ok
checking whether compiler uses NIX_LDFLAGS... ok
checking whether sanitizers are fully functional... ok
/nix/store/cajsw76zdq13gcmz2p7gm6mpcj68qakr-cc-wrapper-test
/nix/store/hg7i7d40vis12kvys9smfrwmafslwwxg-cc-wrapper-test

[GrahamcOfBorg]

Failure on x86_64-linux (full log)

Attempted: tests.cc-wrapper-clang-6, tests.cc-wrapper-libcxx-6

Partial log (click to expand)

shrinking RPATHs of ELF executables and libraries in /nix/store/ygx5qy4z8y85ccq68aizjkqn31hpiazg-libc++-6.0.0
shrinking /nix/store/ygx5qy4z8y85ccq68aizjkqn31hpiazg-libc++-6.0.0/lib/libc++.so.1.0
strip is /nix/store/4qvrxzxa535y8304mk195x50b6p9607d-binutils-2.30/bin/strip
stripping (with command strip and flags -S) in /nix/store/ygx5qy4z8y85ccq68aizjkqn31hpiazg-libc++-6.0.0/lib
patching script interpreter paths in /nix/store/ygx5qy4z8y85ccq68aizjkqn31hpiazg-libc++-6.0.0
checking for references to /build in /nix/store/ygx5qy4z8y85ccq68aizjkqn31hpiazg-libc++-6.0.0...
cannot build derivation '/nix/store/8sgi1f29sx3gb3awrrfsz59fv0q2ai1z-clang-wrapper-6.0.0.drv': 3 dependencies couldn't be built
cannot build derivation '/nix/store/wc26rg59jqqyzl3p4xrk0aq1jfw2hlxi-stdenv-linux.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/sd82d14lv2sbdcwq8bngx45ia5xa3b8j-cc-wrapper-test.drv': 1 dependencies couldn't be built
error: build of '/nix/store/naddhrh3ybn5lfz3xnkfd977axrmik4c-cc-wrapper-test.drv', '/nix/store/sd82d14lv2sbdcwq8bngx45ia5xa3b8j-cc-wrapper-test.drv' failed

[GrahamcOfBorg]

Failure on x86_64-darwin (full log)

Attempted: tests.cc-wrapper-clang-5, tests.cc-wrapper-libcxx-5

Partial log (click to expand)

cannot build derivation '/nix/store/al69lf6a9fa2fy8dz2gzmaw5gjb88r4j-python2.7-cryptography-2.2.2.drv': 21 dependencies couldn't be built
cannot build derivation '/nix/store/pc0r1gjn8qw3cc1s6lvvfk0mbzc9llkj-python2.7-pyOpenSSL-18.0.0.drv': 10 dependencies couldn't be built
cannot build derivation '/nix/store/b055fqh5vdi7r3645y4vvlxa48k8g80b-python2.7-urllib3-1.23.drv': 12 dependencies couldn't be built
cannot build derivation '/nix/store/ymqxm70ph729acqh5kn5vd057h293zms-python2.7-requests-2.19.1.drv': 11 dependencies couldn't be built
cannot build derivation '/nix/store/a9vd8i58fmkmh4x96ppalgsakik67mjs-python2.7-Sphinx-1.7.5.drv': 23 dependencies couldn't be built
cannot build derivation '/nix/store/mr6ffv3ilwaxjmnn212j1g54n6a89hnb-clang-manpages-5.0.2.drv': 7 dependencies couldn't be built
cannot build derivation '/nix/store/kp24nz56sqmvnp38fhdnlzn73cqzbsp5-clang-wrapper-5.0.2.drv': 5 dependencies couldn't be built
cannot build derivation '/nix/store/hwi2jn91wj3bvpg7r3cjkla36killj3h-stdenv-darwin.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/97mmrrkqqj0vmzj3lrns6wjhhjrdiipj-cc-wrapper-test.drv': 1 dependencies couldn't be built
�[31;1merror:�[0m build of '/nix/store/97mmrrkqqj0vmzj3lrns6wjhhjrdiipj-cc-wrapper-test.drv' failed

[GrahamcOfBorg]

Failure on aarch64-linux (full log)

Attempted: tests.cc-wrapper-clang-5, tests.cc-wrapper-libcxx-5

Partial log (click to expand)

[ 83%] Built target clangTidyReadabilityModule
make: *** [Makefile:130: all] Error 2
builder for '/nix/store/14g487rcf8x4wkgj1will5rzgwh8y6ln-clang-5.0.2.drv' failed with exit code 2
cannot build derivation '/nix/store/15wq0pqj581xy45ng0l2xqhmx2bzqx96-clang-wrapper-5.0.2.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/f5kl5682rln4j3pns50894gvklklxc67-clang-wrapper-5.0.2.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/8wsq7abgdz9qb3y0zhbzxd8hvybbd04y-stdenv-linux.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/wn0a5s5c7qsmfl00nk1vg5bchvdf2fbg-stdenv-linux.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/jlihins57dnf87nc2f8h0rmwz6j6b1i8-cc-wrapper-test.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/km9m9kdwmk5q1fgkq9gbgw5cs99971sd-cc-wrapper-test.drv': 1 dependencies couldn't be built
error: build of '/nix/store/jlihins57dnf87nc2f8h0rmwz6j6b1i8-cc-wrapper-test.drv', '/nix/store/km9m9kdwmk5q1fgkq9gbgw5cs99971sd-cc-wrapper-test.drv' failed

[GrahamcOfBorg]

Success on aarch64-linux (full log)

Attempted: tests.cc-wrapper-clang-6, tests.cc-wrapper-libcxx-6

Partial log (click to expand)

checking whether compiler builds valid C++ binaries... ok
checking whether compiler uses NIX_CFLAGS_COMPILE... ok
checking whether compiler uses NIX_LDFLAGS... ok
checking whether sanitizers are fully functional... ok
checking whether compiler builds valid C++ binaries... ok
checking whether compiler uses NIX_CFLAGS_COMPILE... ok
checking whether compiler uses NIX_LDFLAGS... ok
checking whether sanitizers are fully functional... ok
/nix/store/fd50jp8wpbgxmc8dp99i2lxrmyh0qpb1-cc-wrapper-test
/nix/store/khlf22db5c4kqqq77qw9xmv1k22l58d6-cc-wrapper-test

[GrahamcOfBorg]

Failure on x86_64-darwin (full log)

Attempted: tests.cc-wrapper-clang-6, tests.cc-wrapper-libcxx-6

Partial log (click to expand)

cannot build derivation '/nix/store/al69lf6a9fa2fy8dz2gzmaw5gjb88r4j-python2.7-cryptography-2.2.2.drv': 21 dependencies couldn't be built
cannot build derivation '/nix/store/pc0r1gjn8qw3cc1s6lvvfk0mbzc9llkj-python2.7-pyOpenSSL-18.0.0.drv': 10 dependencies couldn't be built
cannot build derivation '/nix/store/b055fqh5vdi7r3645y4vvlxa48k8g80b-python2.7-urllib3-1.23.drv': 12 dependencies couldn't be built
cannot build derivation '/nix/store/ymqxm70ph729acqh5kn5vd057h293zms-python2.7-requests-2.19.1.drv': 11 dependencies couldn't be built
cannot build derivation '/nix/store/a9vd8i58fmkmh4x96ppalgsakik67mjs-python2.7-Sphinx-1.7.5.drv': 23 dependencies couldn't be built
cannot build derivation '/nix/store/zn391d7kj5cck04nqpsjcbhs66aqi2pz-clang-manpages-6.0.0.drv': 7 dependencies couldn't be built
cannot build derivation '/nix/store/m03i5zg2yaa4iha81z4kisn03b7alr9x-clang-wrapper-6.0.0.drv': 7 dependencies couldn't be built
cannot build derivation '/nix/store/zhpczfxi09b5h94yn4xhf1fcakjhz5si-stdenv-darwin.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/pwpa3pg89if15hyf3rwyvdpjkq8z7a8f-cc-wrapper-test.drv': 1 dependencies couldn't be built
�[31;1merror:�[0m build of '/nix/store/pwpa3pg89if15hyf3rwyvdpjkq8z7a8f-cc-wrapper-test.drv' failed

[dtzWill]

Well despite what this says, these all work on at least x86_64-linux in my testing.

[dtzWill]

As mentioned on the PR for llvm 4 with these changes, things look okay so far--and since this goes to staging merging this as well. LMK if there are any problems, will try to check hydra across the next few days.