Use sandboxed clang

Change-Id: I0b9b5b7940b441aba6c6214e621d8997feef90b1
diff --git a/tools/cpp/clang_3p6/x86_64-linux-gnu-ld b/tools/cpp/clang_3p6/x86_64-linux-gnu-ld
new file mode 100755
index 0000000..803a818
--- /dev/null
+++ b/tools/cpp/clang_3p6/x86_64-linux-gnu-ld
@@ -0,0 +1,5 @@
+#!/bin/bash --norc
+
+exec -a ld \
+  ${BAZEL_OUTPUT_ROOT}external/clang_3p6_repo/usr/bin/ld \
+  "$@"