Merge pull request #1075 from sideeffects/send_upstream_defineguard

Guard the cmakedefines in case systems have -D options

Author: jmlait

openvdb/openvdb/version.h.in

@@ -117,13 +117,19 @@
 #endif
 
 /* Denotes whether VDB was built with IMath Half support */
+#ifndef OPENVDB_USE_IMATH_HALF
 #cmakedefine OPENVDB_USE_IMATH_HALF
+#endif
 
 /* Denotes whether VDB was built with Blosc support */
+#ifndef OPENVDB_USE_BLOSC
 #cmakedefine OPENVDB_USE_BLOSC
+#endif
 
 /* Denotes whether VDB was built with ZLIB support */
+#ifndef OPENVDB_USE_ZLIB
 #cmakedefine OPENVDB_USE_ZLIB
+#endif
 
 
 ///////////////////////////////////////////////////////////////////////////////