Add install flags for better dylib bindings

Author: ethanfrey

Dockerfile

@@ -1,5 +1,7 @@
 FROM rust:1.38
 
+# Usage: docker run --rm -v $(pwd):/code confio/go-cosmwasm:demo /root/build_osx.sh
+
 # Install build dependencies
 RUN apt-get update
 RUN apt install -y clang gcc g++ zlib1g-dev libmpc-dev libmpfr-dev libgmp-dev

build/build_osx.sh

@@ -6,5 +6,5 @@ export LIBZ_SYS_STATIC=1
 export CC=o64-clang
 export CXX=o64-clang++
 
-cargo build --release --target x86_64-apple-darwin --features force-osx-x86-64
+RUSTFLAGS="-C link-args=-Wl,-install_name,@rpath/libgo_cosmwasm.dylib" cargo build --release --target x86_64-apple-darwin --features force-osx-x86-64
 cp target/x86_64-apple-darwin/release/deps/libgo_cosmwasm.dylib api