Merge pull request #89 from peternowee/fix-mac-isnan

Use ISNAN() to prevent build error on OS X 10.7

Author: hadley

src/MyBinding.h

@@ -97,7 +97,7 @@ class MyBinding {
       }
       case MY_DATE:
       case MY_DATE_TIME:
-        if (isnan(REAL(col)[i])) {
+        if (ISNAN(REAL(col)[i])) {
           missing = true;
           break;
         } else {