diff --git a/tools/lib/index_log/Makefile b/tools/lib/index_log/Makefile
index 5ad98a2e8d..6e1fa57852 100644
--- a/tools/lib/index_log/Makefile
+++ b/tools/lib/index_log/Makefile
@@ -3,7 +3,7 @@ CXX := g++
 
 index_log: index_log.cc
 	$(eval $@_TMP := $(shell mktemp))
-	$(CXX) -std=gnu++11 -o $($@_TMP) \
+	$(CXX) -std=c++1z -o $($@_TMP) \
     index_log.cc \
     -lcapnp -lkj
 	mv $($@_TMP) $@