[gn] port 249cf35

Author: nico

llvm/utils/gn/secondary/lldb/test/BUILD.gn

@@ -60,7 +60,8 @@ write_lit_cfg("lit_api_site_cfg") {
     "LLDB_TEST_COMMON_ARGS=",
     "LLDB_TEST_USER_ARGS=",
     "LLDB_ENABLE_PYTHON=0",
-    "LLDB_HAS_LIBCXX=0",  # FIXME: support this (?)
+    "LLDB_HAS_LIBCXX=False",  # FIXME: support this (?)
+    "LLDB_TEST_USE_VENDOR_PACKAGES=False",
     "LLDB_LIBS_DIR=",  # FIXME: for shared builds only (?)
     "LLDB_TEST_ARCH=$current_cpu",
     "LLDB_TEST_COMPILER=" + rebase_path("$root_build_dir/bin/clang"),