Allow to compile with new javascript backend

Author: sevanspowell

servant-jsaddle.cabal

@@ -53,7 +53,7 @@ library
     , text          >=1.2.3.0
     , transformers  >=0.5.2.0
 
-  if impl(ghcjs -any)
+  if impl(ghcjs -any) || arch(javascript)
     build-depends: ghcjs-base
 
   -- Servant dependencies.
@@ -72,7 +72,7 @@ library
     , string-conversions  >=0.3     && <0.5
     , transformers-base   >=0.4.4   && <0.5
 
-  if impl(ghc >=8.0)
+  if impl(ghc >=8.0) || arch(javascript)
     ghc-options: -Wno-redundant-constraints
 
 test-suite spec
@@ -82,7 +82,7 @@ test-suite spec
   hs-source-dirs:   test
   main-is:          Spec.hs
 
-  if impl(ghcjs -any)
+  if impl(ghcjs -any) || arch(javascript)
     build-depends:
         base
       , servant-jsaddle