The error is raised by `wasm-ld`: ``` wasm-ld: error: /Users/maxd/.carton/sdk/wasm-5.3-SNAPSHOT-2020-09-23-a/usr/share/wasi-sysroot/lib/wasm32-wasi/ libc.a(__original_main.o): undefined symbol: main ``` The build command is ``` /Users/maxd/.carton/sdk/wasm-5.3-SNAPSHOT-2020-09-23-a/usr/bin/swift \ build -c debug --build-tests --destination /Users/maxd/.carton/sdk/wasm-5.3-SNAPSHOT-2020-09-23-a.json -Xswiftc -color-diagnostics ```