diff --git a/pkgs/development/libraries/libfaketime/default.nix b/pkgs/development/libraries/libfaketime/default.nix
index 65d04cb53f16..3492a07905d8 100644
--- a/pkgs/development/libraries/libfaketime/default.nix
+++ b/pkgs/development/libraries/libfaketime/default.nix
@@ -24,6 +24,8 @@ stdenv.mkDerivation rec {
   PREFIX = placeholder "out";
   LIBDIRNAME = "/lib";
 
+  NIX_CFLAGS_COMPILE = "-Wno-error=cast-function-type -Wno-error=format-truncation";
+
   checkInputs = [ perl ];
 
   meta = with stdenv.lib; {