[xbuild] Bump buildtools to get support for netstandard 1.6

[mono.git] / external / buildtools

diff --git a/external/buildtools b/external/buildtools
index a7dbffc17d029f2d66f56ddc9f50349a1bc0dcfe..9b6ee8686be55a983d886938165b6206cda50772 160000 (submodule)
--- a/external/buildtools
+++ b/external/buildtools
@@ -1 +1 @@
-Subproject commit a7dbffc17d029f2d66f56ddc9f50349a1bc0dcfe
+Subproject commit 9b6ee8686be55a983d886938165b6206cda50772