diff --git a/src/pg/decoder.cr b/src/pg/decoder.cr
index 63a06ccb..63bcc189 100644
--- a/src/pg/decoder.cr
+++ b/src/pg/decoder.cr
@@ -1,5 +1,9 @@
 require "json"
 
+lib LibC
+  fun atoi(str : UInt8*) : Int32
+end
+
 module PG
   alias PGValue = String | Nil | Bool | Int32 | Float32 | Float64 | Time | JSON::Type
 
diff --git a/src/pg/libpq.cr b/src/pg/libpq.cr
index 46ea8424..d17b88bd 100644
--- a/src/pg/libpq.cr
+++ b/src/pg/libpq.cr
@@ -6,7 +6,7 @@ module PG
     alias Int   = Int32
     alias Oid   = Int32
 
-    struct PGconn   end
+    alias PGconn = Void
     enum ConnStatusType
       CONNECTION_OK, CONNECTION_BAD, CONNECTION_STARTED, CONNECTION_MADE,
       CONNECTION_AWAITING_RESPONSE, CONNECTION_AUTH_OK, CONNECTION_SETENV,
@@ -28,7 +28,7 @@ module PG
                           result_format : Int
                         ) : PGresult*
 
-    struct PGresult end
+    alias PGresult = Void
     enum ExecStatusType
       PGRES_EMPTY_QUERY, PGRES_COMMAND_OK, PGRES_TUPLES_OK, PGRES_COPY_OUT,
       PGRES_COPY_IN, PGRES_BAD_RESPONSE, PGRES_NONFATAL_ERROR, PGRES_FATAL_ERROR,