rust-opencvのcargo buildでlibclang.dylib（macOS）がみつからなかったときのメモ

rustでディープラーニングしてみようと思い、

$ cargo new rust-opencv-study

Cargo.toml

[package]
name = "rust-opencv-study"
version = "0.1.0"
authors = ["user.name <user.email>"]
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
opencv = "0.49.1"

の、

$ cargo build

で、こんなとき

   Compiling opencv v0.49.1
error: failed to run custom build command for `opencv v0.49.1`

Caused by:
  process didn't exit successfully: `/Users/takahiro/Documents/source/rust-opencv/target/debug/build/opencv-eee0ce442a19ac9b/build-script-build` (signal: 6, SIGABRT: process abort signal)
  --- stderr
  dyld: Library not loaded: @rpath/libclang.dylib
    Referenced from: /Users/takahiro/Documents/source/rust-opencv/target/debug/build/opencv-eee0ce442a19ac9b/build-script-build
    Reason: image not found

には、

$ ln -s /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/libclang.dylib /usr/local/Cellar/rust/1.49.0_1/lib/rustlib/x86_64-apple-darwin/lib/libclang.dylib

で、

$ cargo build

   Compiling opencv v0.49.1
   Compiling rust-opencv v0.1.0 (/Users/takahiro/Documents/source/rust-opencv)
    Finished dev [unoptimized + debuginfo] target(s) in 2m 24s

ダン、でした。

リファレンス

[@github rust-lang/rust - rust-lld fails with "dyld: Library not loaded: @rpath/libLLVM.dylib" on 1.30.0-nightly (02cb8f2a4 2018-08-29) #53813]
(https://github.com/rust-lang/rust/issues/53813#issuecomment-417375284)