diff --git a/llvm/utils/gn/secondary/lldb/test/BUILD.gn b/llvm/utils/gn/secondary/lldb/test/BUILD.gn
index c49ce21cb8c66..7f99166995dca 100644
--- a/llvm/utils/gn/secondary/lldb/test/BUILD.gn
+++ b/llvm/utils/gn/secondary/lldb/test/BUILD.gn
@@ -52,6 +52,10 @@ write_lit_cfg("lit_api_site_cfg") {
   input = "//lldb/test/API/lit.site.cfg.py.in"
   output = lldb_lit_api_site_cfg_file
   extra_values = [
+    "LIBCXX_LIBRARY_DIR=" + rebase_path("$root_build_dir/lib"),
+    "LIBCXX_GENERATED_INCLUDE_DIR=" +
+        rebase_path("$root_build_dir/include/c++/v1"),
+    "LIBCXX_GENERATED_INCLUDE_TARGET_DIR=",
     "LLDB_BUILD_INTEL_PT=0",
     "LLDB_TEST_COMMON_ARGS=",
     "LLDB_TEST_USER_ARGS=",