  #include "overlapArea.h"
 diff --git a/reproject/spherical_intersect/reproject_slice_c.c b/reproject/spherical_intersect/reproject_slice_c.c
 index 424bb86..a2c45f7 100644
---- a/reproject/spherical_intersect/reproject_slice_c.c
-+++ b/reproject/spherical_intersect/reproject_slice_c.c
+--- reproject/spherical_intersect/reproject_slice_c.c
++++ reproject/spherical_intersect/reproject_slice_c.c
 @@ -1,7 +1,7 @@
  #include "overlapArea.h"
  #include "reproject_slice_c.h"

diff --git a/reproject/spherical_intersect/mNaN.h b/reproject/spherical_intersect/mNaN.h
index f8cd61f..3638736 100644
--- a/reproject/spherical_intersect/mNaN.h
+++ b/reproject/spherical_intersect/mNaN.h
@@ -4,4 +4,4 @@
 
 #include <math.h>

+#define mNaN(x) _isnan(x) || !_finite(x)
diff --git a/reproject/spherical_intersect/overlapArea.c b/reproject/spherical_intersect/overlapArea.c
index 56c7987..ac7061d 100644
--- reproject/spherical_intersect/overlapArea.c
+++ reproject/spherical_intersect/overlapArea.c
@@ -4,6 +4,7 @@
  */
 
