diff --git a/vendor/double-conversion/upstream/.gitignore b/vendor/double-conversion/upstream/.gitignore
new file mode 100644
index 00000000000..e8352aeb6ef
--- /dev/null
+++ b/vendor/double-conversion/upstream/.gitignore
@@ -0,0 +1,9 @@
+.sconsign.dblite
+*.o
+*.obj
+msvc/Release/
+msvc/Debug/
+*.suo
+*.opensdf
+*.sdf
+*.user