From: hololeap <hololeap@protonmail.com>
Signed-off-by: hololeap <hololeap@protonmail.com>

Add new USE flag: executable
This toggles building the executable. Since this seems to be the primary
purpose of the package, it is enabled by default.

--- markdown-unlit-0.5.1/markdown-unlit.cabal.bak	2021-08-28 01:55:59.160717350 -0600
+++ markdown-unlit-0.5.1/markdown-unlit.cabal	2021-08-28 01:58:49.820717433 -0600
@@ -35,7 +35,13 @@
       Paths_markdown_unlit
   default-language: Haskell2010
 
+flag executable
+  description: Build executable
+  default: True
+
 executable markdown-unlit
+  if !flag(executable)
+      buildable: False
   main-is: Main.hs
   other-modules:
       Paths_markdown_unlit