llvm, top-level: Baby steps towards cross support

[Ericson2314]

Motivation for this change

Tried to do what I could while preserving hashes (always a good test!).

• Less wrapper "helper" function madness
• Clang wrapper and stdenvs at least try to refer to adjacent stages.
• Removed some old dead clean stuff

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option build-use-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/)
• Fits CONTRIBUTING.md.

---

[GrahamcOfBorg]

Success on x86_64-darwin (full log)

Attempted: llvm

Partial log (click to expand)

/nix/store/c0halv3c1zxax8dj7zwsyg0jlwicp64z-llvm-5.0.1

[GrahamcOfBorg]

Success on aarch64-linux (full log)

Attempted: llvm

Partial log (click to expand)

/nix/store/pskvivaqfn92jiiw30kwg32d33d1ak48-llvm-5.0.1-python/share/opt-viewer/opt-stats.py: interpreter directive changed from "/usr/bin/env python2.7" to "/nix/store/vhz9s1dzzbndz032dysnixj8mxyfl30s-python-2.7.14/bin/python2.7"
/nix/store/pskvivaqfn92jiiw30kwg32d33d1ak48-llvm-5.0.1-python/share/opt-viewer/opt-diff.py: interpreter directive changed from "/usr/bin/env python2.7" to "/nix/store/vhz9s1dzzbndz032dysnixj8mxyfl30s-python-2.7.14/bin/python2.7"
checking for references to /build in /nix/store/pskvivaqfn92jiiw30kwg32d33d1ak48-llvm-5.0.1-python...
shrinking RPATHs of ELF executables and libraries in /nix/store/35q99mahim3gihys7d7g6xciwfika7fi-llvm-5.0.1-lib
shrinking /nix/store/35q99mahim3gihys7d7g6xciwfika7fi-llvm-5.0.1-lib/lib/libLLVM-5.0.so
strip is /nix/store/jk6j4lh9v5mvjdbdc35sj0zffhhf6s56-binutils-2.30/bin/strip
stripping (with command strip and flags -S) in /nix/store/35q99mahim3gihys7d7g6xciwfika7fi-llvm-5.0.1-lib/lib
patching script interpreter paths in /nix/store/35q99mahim3gihys7d7g6xciwfika7fi-llvm-5.0.1-lib
checking for references to /build in /nix/store/35q99mahim3gihys7d7g6xciwfika7fi-llvm-5.0.1-lib...
/nix/store/04vd1yznqdzqpphj946hnkc88xaxf59x-llvm-5.0.1

[GrahamcOfBorg]

Failure on x86_64-linux (full log)

Attempted: llvm

Partial log (click to expand)

Dependee "/build/llvm/build/CMakeFiles/CMakeDirectoryInformation.cmake" is newer than depender "/build/llvm/build/CMakeFiles/check-all.dir/depend.internal".
Scanning dependencies of target check-all
make[3]: Leaving directory '/build/llvm/build'
make -f CMakeFiles/check-all.dir/build.make CMakeFiles/check-all.dir/build
make[3]: Entering directory '/build/llvm/build'
[100%] Running all regression tests
/nix/store/l9j2jsc9flrbmpf799nw9wdq59gpwms8-python-2.7.14/bin/python2.7 /build/llvm/utils/lit/lit.py -sv --param llvm_site_config=/build/llvm/build/test/lit.site.cfg --param llvm_unit_site_config=/build/llvm/build/test/Unit/lit.site.cfg /build/llvm/build/test
-- Testing: 21436 tests, 4 threads --
building of '/nix/store/ymm68lzgkawgpif7q4bnxh9x9pfzxkq4-llvm-5.0.1.drv' timed out after 1800 seconds
error: build of '/nix/store/ymm68lzgkawgpif7q4bnxh9x9pfzxkq4-llvm-5.0.1.drv' failed

[GrahamcOfBorg]

Success on x86_64-darwin (full log)

Attempted: llvm

Partial log (click to expand)

/nix/store/c0halv3c1zxax8dj7zwsyg0jlwicp64z-llvm-5.0.1

[GrahamcOfBorg]

Success on x86_64-linux (full log)

Attempted: llvm

Partial log (click to expand)

these paths will be fetched (37.22 MiB download, 234.41 MiB unpacked):
  /nix/store/87k8q7x4j1mzgq4r69lkvsyhvk47xrcr-llvm-5.0.1-lib
  /nix/store/khmzmxzyxik5v4vkg8n0l8p6kfcx3x95-llvm-5.0.1
copying path '/nix/store/87k8q7x4j1mzgq4r69lkvsyhvk47xrcr-llvm-5.0.1-lib' from 'https://cache.nixos.org'...
copying path '/nix/store/khmzmxzyxik5v4vkg8n0l8p6kfcx3x95-llvm-5.0.1' from 'https://cache.nixos.org'...
/nix/store/khmzmxzyxik5v4vkg8n0l8p6kfcx3x95-llvm-5.0.1

[GrahamcOfBorg]

Success on aarch64-linux (full log)

Attempted: llvm

Partial log (click to expand)

/nix/store/04vd1yznqdzqpphj946hnkc88xaxf59x-llvm-5.0.1

[GrahamcOfBorg]

Success on x86_64-darwin (full log)

Attempted: llvm

Partial log (click to expand)

/nix/store/c0halv3c1zxax8dj7zwsyg0jlwicp64z-llvm-5.0.1

[GrahamcOfBorg]

Success on aarch64-linux (full log)

Attempted: llvm

Partial log (click to expand)

/nix/store/04vd1yznqdzqpphj946hnkc88xaxf59x-llvm-5.0.1

[GrahamcOfBorg]

Success on x86_64-linux (full log)

Attempted: llvm

Partial log (click to expand)

these paths will be fetched (37.22 MiB download, 234.41 MiB unpacked):
  /nix/store/87k8q7x4j1mzgq4r69lkvsyhvk47xrcr-llvm-5.0.1-lib
  /nix/store/khmzmxzyxik5v4vkg8n0l8p6kfcx3x95-llvm-5.0.1
copying path '/nix/store/87k8q7x4j1mzgq4r69lkvsyhvk47xrcr-llvm-5.0.1-lib' from 'https://cache.nixos.org'...
copying path '/nix/store/khmzmxzyxik5v4vkg8n0l8p6kfcx3x95-llvm-5.0.1' from 'https://cache.nixos.org'...
/nix/store/khmzmxzyxik5v4vkg8n0l8p6kfcx3x95-llvm-5.0.1

[Ericson2314]

OK the top commit that fixes the overriding also causes a mass rebuild, so removed it. [But then ofborg didn't update labels because the testing was cached.]