lib: disable doctests when building with ghc 8.4 on mac

[ci skip]

hledger-lib/hledger-lib.cabal

@@ -2,7 +2,7 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 916d92693555f9b8362107e6b607319726dac39eb253d530485abf0dd0abcdeb
+-- hash: 3696048cb5e70ae9644121c85e0f9252ebcaa3d2813c8ea03cdae6c66fe6210a
 
 name:           hledger-lib
 version:        1.5.99
@@ -225,6 +225,8 @@ test-suite doctests
   if (!impl(ghc >= 8.0))
     build-depends:
         semigroups ==0.18.*
+  if impl(ghc >= 8.4) && os(darwin)
+    buildable: False
   default-language: Haskell2010
 
 test-suite easytests

hledger-lib/package.yaml

@@ -150,6 +150,10 @@ tests:
     dependencies:
     - doctest >=0.8
     - Glob >=0.7
+    # doctest won't run with ghc 8.4 on mac right now, https://github.com/sol/hpack/issues/199
+    when:
+    - condition: impl(ghc >= 8.4) && os(darwin)
+      buildable: false
 
   hunittests:
     main: hunittests.hs