add requirement

lakefile.lean

@@ -10,12 +10,27 @@ def moreServerArgs := #[
 -- These settings only apply during `lake build`, but not in VSCode editor.
 def moreLeanArgs := moreServerArgs
 
+-- These are additional settings which do not affect the lake hash,
+-- so they can be enabled in CI and disabled locally or vice versa.
+-- Warning: Do not put any options here that actually change the olean files,
+-- or inconsistent behavior may result
+def weakLeanArgs : Array String :=
+  if get_config? CI |>.isSome then
+    #["-DwarningAsError=true"]
+  else
+    #[]
+
 package «carleson» where
   moreServerArgs := moreServerArgs
 
 require mathlib from git
   "https://github.com/leanprover-community/mathlib4.git"
 
+-- This is run only if we're in `dev` mode. This is so not everyone has to build doc-gen
+meta if get_config? env = some "dev" then
+require «doc-gen4» from git
+  "https://github.com/leanprover/doc-gen4" @ "main"
+
 @[default_target]
 lean_lib «Carleson» where
   moreLeanArgs := moreLeanArgs