Windows: Switch to the dynamic C runtime

This change switches windows to the dynamic C runtime
avoiding issues coming from mixing the static and dynamic
runtime like the ones outlined in [1]

[1] https://developer.blender.org/D5387#122165

Differential Revision: https://developer.blender.org/D6175

Reviewed by: @Sergey

intern/openvdb/CMakeLists.txt

@@ -40,6 +40,12 @@ if(WITH_OPENVDB)
     ${OPENVDB_DEFINITIONS}
   )
 
+  if(WIN32)
+    add_definitions(
+      -DOPENVDB_STATICLIB
+    )
+  endif()
+
   if(WITH_OPENVDB_3_ABI_COMPATIBLE)
     add_definitions(
       -DOPENVDB_3_ABI_COMPATIBLE