diff --git a/pkgs/applications/backup/timeshift/unwrapped.nix b/pkgs/applications/backup/timeshift/unwrapped.nix
index 3fbaed4b21be..ebc37cfe55ff 100644
--- a/pkgs/applications/backup/timeshift/unwrapped.nix
+++ b/pkgs/applications/backup/timeshift/unwrapped.nix
@@ -57,6 +57,10 @@ stdenv.mkDerivation rec {
     xapp
   ];
 
+  env = lib.optionalAttrs stdenv.cc.isGNU {
+    NIX_CFLAGS_COMPILE = "-Wno-error=implicit-function-declaration";
+  };
+
   meta = with lib; {
     description = "System restore tool for Linux";
     longDescription = ''