diff --git a/pkgs/development/tools/misc/complexity/default.nix b/pkgs/development/tools/misc/complexity/default.nix
index 076a68b81374..cfdc35f1b346 100644
--- a/pkgs/development/tools/misc/complexity/default.nix
+++ b/pkgs/development/tools/misc/complexity/default.nix
@@ -19,6 +19,13 @@ stdenv.mkDerivation rec {
 
   doCheck = true;
 
+  preBuild = ''
+    sed -i -e '/gets is a security/d' lib/stdio.in.h
+    sed -i '42 i\
+      #undef false\
+      #undef true' src/complexity.h
+  '';
+
   meta = {
     description = "GNU Complexity, C code complexity measurement tool";