pkg/54321: lang/rust build fails on Arch Linux

[triaxx%NetBSD.org@localhost]

>Number:         54321
>Category:       pkg
>Synopsis:       lang/rust build fails on Arch Linux
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Jun 24 05:10:00 +0000 2019
>Originator:     Frédéric Fauberteau
>Release:        pkgsrc (HEAD)
>Organization:
>Environment:
System: Linux guardian 5.1.9-arch1-1-ARCH #1 SMP PREEMPT Tue Jun 11 16:18:09 UTC 2019 x86_64 GNU/Linux
Architecture: x86_64
Machine: amd64
>Description:
If needed, the complete log is available here:
http://pkg.triaxx.org/pub/pkgsrc/logs/devel/rust/rust-1.35.0/pkgsrc-build.log

Building stage0 codegen artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu, llvm)
running: "/home/triaxx/netbsd/pkgsrc/lang/rust/work/rust-bootstrap/bin/cargo" "build" "--target" "x86_64-unknown-linux-gnu" "-j" "1" "--release" "--frozen" "--manifest-path" "/home/triaxx/netbsd/pkgsrc/lang/rust/work/rustc-1.35.0-src/src/librustc_codegen_llvm/Cargo.toml" "--features" "" "--message-format" "json"
   Compiling libc v0.2.51
   Compiling cc v1.0.28
   Compiling build_helper v0.1.0 (/home/triaxx/netbsd/pkgsrc/lang/rust/work/rustc-1.35.0-src/src/build_helper)
   Compiling rustc_codegen_llvm v0.0.0 (/home/triaxx/netbsd/pkgsrc/lang/rust/work/rustc-1.35.0-src/src/librustc_codegen_llvm)
   Compiling rustc-demangle v0.1.10
   Compiling rustc_llvm v0.0.0 (/home/triaxx/netbsd/pkgsrc/lang/rust/work/rustc-1.35.0-src/src/librustc_llvm)
error: failed to run custom build command for `rustc_llvm v0.0.0 (/home/triaxx/netbsd/pkgsrc/lang/rust/work/rustc-1.35.0-src/src/librustc_llvm)`
process didn't exit successfully: `/home/triaxx/netbsd/pkgsrc/lang/rust/work/rustc-1.35.0-src/build/x86_64-unknown-linux-gnu/stage0-codegen/release/build/rustc_llvm-ba9d9be5ce7e72db/build-script-build` (exit code: 101)
--- stdout
cargo:rerun-if-env-changed=REAL_LIBRARY_PATH_VAR
cargo:rerun-if-env-changed=REAL_LIBRARY_PATH
cargo:rerun-if-changed=/home/triaxx/netbsd/pkgsrc/lang/rust/work/rustc-1.35.0-src/build/x86_64-unknown-linux-gnu/llvm/build/bin/llvm-config
cargo:rerun-if-env-changed=LLVM_CONFIG

--- stderr
/home/triaxx/netbsd/pkgsrc/lang/rust/work/rustc-1.35.0-src/build/x86_64-unknown-linux-gnu/llvm/build/bin/llvm-config: error while loading shared libraries: libLLVM-8-rust-1.35.0-stable.so: cannot open shared object file: No such file or directory
thread 'main' panicked at 'command did not execute successfully: "/home/triaxx/netbsd/pkgsrc/lang/rust/work/rustc-1.35.0-src/build/x86_64-unknown-linux-gnu/llvm/build/bin/llvm-config" "--version"
expected success, got: exit code: 127', src/build_helper/lib.rs:134:9
note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.

command did not execute successfully: "/home/triaxx/netbsd/pkgsrc/lang/rust/work/rust-bootstrap/bin/cargo" "build" "--target" "x86_64-unknown-linux-gnu" "-j" "1" "--release" "--frozen" "--manifest-path" "/home/triaxx/netbsd/pkgsrc/lang/rust/work/rustc-1.35.0-src/src/librustc_codegen_llvm/Cargo.toml" "--features" "" "--message-format" "json"
expected success, got: exit code: 101
Traceback (most recent call last):
  File "./x.py", line 11, in <module>
    bootstrap.main()
  File "/home/triaxx/netbsd/pkgsrc/lang/rust/work/rustc-1.35.0-src/src/bootstrap/bootstrap.py", line 849, in main
    bootstrap(help_triggered)
  File "/home/triaxx/netbsd/pkgsrc/lang/rust/work/rustc-1.35.0-src/src/bootstrap/bootstrap.py", line 835, in bootstrap
    run(args, env=env, verbose=build.verbose)
  File "/home/triaxx/netbsd/pkgsrc/lang/rust/work/rustc-1.35.0-src/src/bootstrap/bootstrap.py", line 141, in run
    raise RuntimeError(err)
RuntimeError: failed to run: /home/triaxx/netbsd/pkgsrc/lang/rust/work/rustc-1.35.0-src/build/bootstrap/debug/bootstrap -v build -j 1
*** Error code 1

Stop.
bmake[1]: stopped in /home/triaxx/netbsd/pkgsrc/lang/rust
*** Error code 1

Stop.
bmake: stopped in /home/triaxx/netbsd/pkgsrc/lang/rust
>How-To-Repeat:
cd lang/rust && bmake build
>Fix:
The following runs but I have no idea how to provide a fix:
$ LD_LIBRARY_PATH="work/rustc-1.35.0-src/build/x86_64-unknown-linux-gnu/llvm/build/lib" work/rustc-
1.35.0-src/build/x86_64-unknown-linux-gnu/llvm/build/bin/llvm-config --version
8.0.0-rust-1.35.0-stable