Support :process-shim compiler option

[minttu]

https://clojurescript.org/reference/compiler-options#process-shim

[vemv]

Needless to say, the issue manifests itself in the following way:

------ Figwheel Configuration Error ------

Found unrecognized key :process-shim at path (:cljsbuild :builds :unit :compiler)
Must be one of: :infer-externs, :output-dir, :closure-warnings, :closure-defines, :static-fns, :dump-core, :externs, :ups-libs, :optimize-constants, :cache-analysis, :modules, :elide-asserts, :language-out, :optimizations, :recompile-dependents, :source-map-path, :closure-extra-annotations, :ups-foreign-libs, :parallel-build, :verbose, :warnings, :preloads, :source-map-inline, :anon-fn-naming-policy, :output-to, :source-map-timestamp, :preamble, :asset-path, :print-input-delimiter, :output-wrapper, :ups-externs, :hashbang, :source-map, :watch-fn, :foreign-libs, :libs, :target, :pseudo-names, :devcards, :external-config, :compiler-stats, :main, :pretty-print, :closure-output-charset, :language-in, :warning-handlers or :emit-constants

  {:cljsbuild
   {:builds
    {:unit
     {:compiler
      {:output-dir "resources/test/out"
       :closure-defines {#, #, #, #}
       :externs
       [...]
       :process-shim false
       ^---- The key :process-shim is unrecognized
       :optimizations :none
       :parallel-build true
       ...}}}}}

[bhauman]

gotcha