Add cast to silence warning.
diff --git a/src/dnssec-openssl.c b/src/dnssec-openssl.c
index 3151cdb..e4cc3ea 100644
--- a/src/dnssec-openssl.c
+++ b/src/dnssec-openssl.c
@@ -180,7 +180,7 @@
     for (i = 0; i < POOL_SIZE; ++i)
       if (!(pool_used & (1 << i)))
         {
-          ret = &Pool[i];
+          ret = (VerifyAlgCtx*)&Pool[i];
           pool_used |= 1 << i;
           break;
         }