ANN: ClojureScript 1.9.518, `async` issue resolved

[David Nolen]

ClojureScript, the Clojure compiler that emits JavaScript source code.

README and source code: https://github.com/clojure/clojurescript

Leiningen dependency information:

[org.clojure/clojurescript "1.9.518"]

This release bumps Closure Compiler, finally resolving the issue with core.async.

As always feedback welcome!

## 1.9.518

### Enhancements

* CLJS-1973: Add support for `:npm-deps` in upstream `deps.cljs`

* CLJS-1968: Enable calling JS modules that export a single function

* CLJS-1960: Require CommonJS modules directly from a ClojureScript namespace

### Changes

* CLJS-2006: Upgrade Closure Compiler to April 2017 release

### Fixes 

* CLJS-1497: `find` on an associative collection does not return collection key

* CLJS-1996: Support correct checking of :preloads when :optimizations not specified

* CLJS-1994: assoc on nil returns PHM (expected PAM)

* CLJS-1988: add :npm-deps to recognized compiler options

* Fix tiny bug in index-node-modules when no second argument is given

* CLJS-1985: `index-node-modules` should pass opts to `node-inputs`

* CLJS-1987: don't index node modules blindly

* CLJS-1519 Collection invoke errors report arity off by 1

* CLJS-1964: Validate that `:target :nodejs` and no optimizations requires a `:main` option to be present

* CLJS-1956: Add missing JS reserved keywords

* CLJS-1983: res -> mres in spec.cljs

* CLJS-1978: port CLJ-2035

* CLJS-1979: port CLJ-2043 (fix s/form of s/conformer)

* CLJS-1980: port CLJ-2100 (s/nilable form should retain original spec form)

* CLJS-1976: hash-map assoc stackoverflow

* CLJS-1957: Process JS modules errors and warnings don't get printed

* CLJS-1868 - Output simpler dependency rel paths when compiling with Closure libs

* CLJS-1967: Missing ^boolean for removed-leaf? in THM impl

[David Nolen]

I just cut 1.9.521. The only change was to fix a regression to :foreign-libs when there are multiple entries which use the same :file.

David