diff --git a/pkgs/build-support/setup-hooks/make-wrapper.sh b/pkgs/build-support/setup-hooks/make-wrapper.sh
index f75b285bacf2..5d5ddcaa8d72 100644
--- a/pkgs/build-support/setup-hooks/make-wrapper.sh
+++ b/pkgs/build-support/setup-hooks/make-wrapper.sh
@@ -11,15 +11,18 @@ assertExecutable() {
 # makeWrapper EXECUTABLE ARGS
 
 # ARGS:
-# --argv0 NAME      : set name of executed process to NAME
-#                     (otherwise it’s called …-wrapped)
-# --set   VAR VAL   : add VAR with value VAL to the executable’s environment
-# --unset VAR       : remove VAR from the environment
-# --run   COMMAND   : run command before the executable
-#                     The command can push extra flags to a magic list variable
-#                     extraFlagsArray, which are then added to the invocation
-#                     of the executable
-# --add-flags FLAGS : add FLAGS to invocation of executable
+# --argv0       NAME    : set name of executed process to NAME
+#                         (otherwise it’s called …-wrapped)
+# --set         VAR VAL : add VAR with value VAL to the executable’s
+#                         environment
+# --set-default VAR VAL : like --set, but only adds VAR if not already set in
+#                         the environment
+# --unset       VAR     : remove VAR from the environment
+# --run         COMMAND : run command before the executable
+#                         The command can push extra flags to a magic list
+#                         variable extraFlagsArray, which are then added to
+#                         the invocation of the executable
+# --add-flags   FLAGS   : add FLAGS to invocation of executable
 
 # --prefix          ENV SEP VAL   : suffix/prefix ENV with VAL, separated by SEP
 # --suffix