diff --git a/pkgs/applications/audio/orca-c/default.nix b/pkgs/applications/audio/orca-c/default.nix
index 420055884b45..be40def26441 100644
--- a/pkgs/applications/audio/orca-c/default.nix
+++ b/pkgs/applications/audio/orca-c/default.nix
@@ -13,6 +13,9 @@ stdenv.mkDerivation {
 
   postPatch = ''
     patchShebangs tool
+    sed -i tool \
+      -e 's@ncurses_dir=.*@ncurses_dir="${ncurses}"@' \
+      -e 's@portmidi_dir=.*@portmidi_dir="${portmidi}"@' tool
   '';
 
   installPhase = ''