--- src/dm/impls/plex/plexcgns.c~	2015-06-09 22:24:49.000000000 +0100
+++ src/dm/impls/plex/plexcgns.c	2015-07-04 23:16:15.861601437 +0100
@@ -1,6 +1,7 @@
 #define PETSCDM_DLL
 #include <petsc/private/dmpleximpl.h>    /*I   "petscdmplex.h"   I*/
 
+#undef I
 #if defined(PETSC_HAVE_CGNS)
 #include <cgnslib.h>
 #include <cgns_io.h>