diff --git a/libs/libxx/libcxx.defs b/libs/libxx/libcxx.defs
index 4fcb993483e..c72850ab582 100644
--- a/libs/libxx/libcxx.defs
+++ b/libs/libxx/libcxx.defs
@@ -24,7 +24,8 @@ VERSION=12.0.0
 #	$(Q) curl -O -L https://github.com/llvm/llvm-project/releases/download/llvmorg-$(VERSION)/libcxx-$(VERSION).src.tar.xz
 
 #libcxx: libcxx-$(VERSION).src.tar.xz
-#	$(Q) tar -xf libcxx-$(VERSION).src.tar.xz
+#	$(Q) tar -xf libcxx-$(VERSION).src.tar.xz \
+#	         --exclude libcxx-$(VERSION).src/test/std/pstl
 #	$(Q) mv libcxx-$(VERSION).src libcxx
 #	$(Q) touch $@