diff --git a/pkgs/development/libraries/glibc/default.nix b/pkgs/development/libraries/glibc/default.nix
index 8b17ff9e558..8a450959c6b 100644
--- a/pkgs/development/libraries/glibc/default.nix
+++ b/pkgs/development/libraries/glibc/default.nix
@@ -10,6 +10,12 @@ callPackage ./common.nix { inherit stdenv; } {
 
     inherit withLinuxHeaders profilingLibraries installLocales withGd;
 
+    # Note:
+    # Things you write here override, and do not add to,
+    # the values in `common.nix`.
+    # (For example, if you define `patches = [...]` here, it will
+    # override the patches in `common.nix`.)
+
     NIX_NO_SELF_RPATH = true;
 
     postConfigure = ''