diff --git a/ext/f2c_libs/.cvsignore b/ext/f2c_libs/.cvsignore
index 36d6bdc5f..fff405aff 100644
--- a/ext/f2c_libs/.cvsignore
+++ b/ext/f2c_libs/.cvsignore
@@ -3,3 +3,5 @@ arith.h
 signal1.h
 sysdep1.h
 makefile*
+arithchk.ilk
+f2c_arithchk.pdb
diff --git a/ext/f2c_libs/arith.hwin32 b/ext/f2c_libs/arith.hwin32
new file mode 100644
index 000000000..9746f9c1c
--- /dev/null
+++ b/ext/f2c_libs/arith.hwin32
@@ -0,0 +1,3 @@
+#define IEEE_8087
+#define Arith_Kind_ASL 1
+#define Double_Align