diff --git a/ext/iconv/.cvsignore b/ext/iconv/.cvsignore
new file mode 100644
index 0000000000..fc802ff1c2
--- /dev/null
+++ b/ext/iconv/.cvsignore
@@ -0,0 +1,2 @@
+Makefile
+mkmf.log
diff --git a/ext/racc/cparse/.cvsignore b/ext/racc/cparse/.cvsignore
new file mode 100644
index 0000000000..fc802ff1c2
--- /dev/null
+++ b/ext/racc/cparse/.cvsignore
@@ -0,0 +1,2 @@
+Makefile
+mkmf.log
diff --git a/ext/stringio/.cvsignore b/ext/stringio/.cvsignore
new file mode 100644
index 0000000000..fc802ff1c2
--- /dev/null
+++ b/ext/stringio/.cvsignore
@@ -0,0 +1,2 @@
+Makefile
+mkmf.log
diff --git a/ext/strscan/.cvsignore b/ext/strscan/.cvsignore
new file mode 100644
index 0000000000..fc802ff1c2
--- /dev/null
+++ b/ext/strscan/.cvsignore
@@ -0,0 +1,2 @@
+Makefile
+mkmf.log