diff --git a/pkgs/development/tools/analysis/splint/default.nix b/pkgs/development/tools/analysis/splint/default.nix
index fa35bf32b445..fe528974e664 100644
--- a/pkgs/development/tools/analysis/splint/default.nix
+++ b/pkgs/development/tools/analysis/splint/default.nix
@@ -18,6 +18,10 @@ stdenv.mkDerivation rec {
 
   buildInputs = [ flex ];
 
+  buildFlags = [
+    "CFLAGS=-std=gnu99"
+  ];
+
   doCheck = true;
 
   meta = {