diff --git a/pkgs/applications/science/logic/easycrypt/default.nix b/pkgs/applications/science/logic/easycrypt/default.nix
index 36ff9f2046f8..2869bcd6e1e3 100644
--- a/pkgs/applications/science/logic/easycrypt/default.nix
+++ b/pkgs/applications/science/logic/easycrypt/default.nix
@@ -22,11 +22,12 @@ stdenv.mkDerivation rec {
     batteries
     dune-build-info
     inifiles
+    why3
     yojson
     zarith
   ];
 
-  propagatedBuildInputs = [ why3 ];
+  propagatedBuildInputs = [ why3.out ];
 
   strictDeps = true;
 
diff --git a/pkgs/applications/science/logic/why3/default.nix b/pkgs/applications/science/logic/why3/default.nix
index 758d11e4252a..1676ca4c2a4f 100644
--- a/pkgs/applications/science/logic/why3/default.nix
+++ b/pkgs/applications/science/logic/why3/default.nix
@@ -55,8 +55,15 @@ stdenv.mkDerivation rec {
     (lib.enableFeature ideSupport "ide")
   ];
 
+  outputs = [ "out" "dev" ];
+
   installTargets = [ "install" "install-lib" ];
 
+  postInstall = ''
+    mkdir -p $dev/lib
+    mv $out/lib/ocaml $dev/lib/
+  '';
+
   passthru.withProvers = callPackage ./with-provers.nix {};
 
   meta = with lib; {
diff --git a/pkgs/development/tools/analysis/frama-c/default.nix b/pkgs/development/tools/analysis/frama-c/default.nix
index 0ff3e6ad1af6..1bf477cf3d16 100644
--- a/pkgs/development/tools/analysis/frama-c/default.nix
+++ b/pkgs/development/tools/analysis/frama-c/default.nix
@@ -20,7 +20,7 @@ let
     ppx_deriving_yojson
     ppx_import
     stdlib-shims
-    why3
+    why3.dev
     re
     result
     seq