build: keep libc++ around

MarshallOfSound · MarshallOfSound · commit 91f944e3741b · 2020-10-26T18:19:50.000-07:00
diff --git a/.circleci/config.yml b/.circleci/config.yml
@@ -681,6 +681,8 @@ step-persist-data-for-tests: &step-persist-data-for-tests
       - src/third_party/nan
       - src/third_party/llvm-build
       - src/build/linux
+      - src/buildtools/third_party/libc++
+      - src/buildtools/third_party/libc++abi
 
 step-electron-dist-unzip: &step-electron-dist-unzip
   run:
