diff --git a/ext/bigdecimal/.cvsignore b/ext/bigdecimal/.cvsignore
new file mode 100644
index 0000000000..4088712231
--- /dev/null
+++ b/ext/bigdecimal/.cvsignore
@@ -0,0 +1,3 @@
+Makefile
+mkmf.log
+*.def
diff --git a/ext/zlib/.cvsignore b/ext/zlib/.cvsignore
new file mode 100644
index 0000000000..4088712231
--- /dev/null
+++ b/ext/zlib/.cvsignore
@@ -0,0 +1,3 @@
+Makefile
+mkmf.log
+*.def