Replace target flags with --target

This commit deprecates the `--web`, `--no-modules`, and `--nodejs` flags
in favor of one `--target` flag. The motivation for this commit is to be
consistent between `wasm-bindgen` and `wasm-pack` so documentation for
one is applicable for the other (so we don't have to document everywhere
what the translation is between flags). Additionally this should make it
a bit easier to add new targets (if necessary) in the future as it won't
add to the proliferation of flags.

For now the old flags (like `--web`) continue to be accepted, but
they'll be removed during the next set of breaking changes for
`wasm-bindgen`.

examples/raytrace-parallel/build.sh

@@ -1,25 +0,0 @@
-#!/bin/sh
-
-set -ex
-
-# Two critical steps are required here to get this working:
-#
-# * First, the Rust standard library needs to be compiled. The default version
-#   is not compatible with atomics so we need to compile a version, with xargo,
-#   that is compatible.
-#
-# * Next we need to compile everything with the `atomics` feature enabled,
-#   ensuring that LLVM will generate atomic instructions and such.
-RUSTFLAGS='-C target-feature=+atomics' \
-  rustup run nightly xargo build --target wasm32-unknown-unknown --release
-
-# Threading support is disabled by default in wasm-bindgen, so use an env var
-# here to turn it on for our bindings generation. Also note that webpack isn't
-# currently compatible with atomics, so we go with the --no-modules output.
-WASM_BINDGEN_THREADS=1 \
-  cargo run --manifest-path ../../crates/cli/Cargo.toml \
-    --bin wasm-bindgen -- \
-    ../../target/wasm32-unknown-unknown/release/raytrace_parallel.wasm --out-dir . \
-    --no-modules
-
-python3 -m http.server