Fixed csharp-sqlite support

Error occurs when tried to compile sqlite-net against latest csharp-sqlite from http://code.google.com/p/csharp-sqlite/, (3.7.7.1 changeset 71 or latest change set http://code.google.com/p/csharp-sqlite/source/detail?r=23fae9fe4149aa39aa5a1a5f7414a92448f8b7f4).

To fix the compilation, I think a conditional statement should be modified. The change is attached. Please review.