diff --git a/pkgs/build-support/clang-wrapper/setup-hook.sh b/pkgs/build-support/clang-wrapper/setup-hook.sh
index 0724d081290..f7687651eaf 100644
--- a/pkgs/build-support/clang-wrapper/setup-hook.sh
+++ b/pkgs/build-support/clang-wrapper/setup-hook.sh
@@ -31,3 +31,6 @@ fi
 if test -n "@coreutils@"; then
     addToSearchPath PATH @coreutils@/bin
 fi
+
+: ${CXX:=clang++}
+export CXX