Build with static libgcc

To make sure it won't require extra dependencies on windows

Change-Id: I8a94cc8060194328a6cd73eaf9aca270297082df
Reviewed-on: http://review.couchbase.org/33529
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>