diff --git a/pkgs/development/tools/parsing/flexc++/default.nix b/pkgs/development/tools/parsing/flexc++/default.nix
index 4fef3731962..c01c374b5fd 100644
--- a/pkgs/development/tools/parsing/flexc++/default.nix
+++ b/pkgs/development/tools/parsing/flexc++/default.nix
@@ -18,7 +18,7 @@ stdenv.mkDerivation rec {
 
   postPatch = ''
     substituteInPlace INSTALL.im --replace /usr $out
-    patchShebangs ./build
+    patchShebangs .
   '';
 
   buildPhase = ''
@@ -28,11 +28,7 @@ stdenv.mkDerivation rec {
   '';
 
   installPhase = ''
-    ./build install man
-    ./build install manual
-    ./build install program
-    ./build install skel
-    ./build install std
+    ./build install x
   '';
 
   meta = with stdenv.lib; {