trivial patch for pg_dump blob problem

Hello!

  In case when there some error have occured getting blob data,
  instead of failing gracefully failing, it will probably segfault
  or loop forever.
  All of this will happen only on platforms where size_t is unsigned
  (e.g. on Linux systems modulo Linux/sparc32).
  Simple non-intrusive patch is below ;)

Bye,
    Oleg

--- postgresql-7.3.2/src/bin/pg_dump/pg_dump.c.orig    Sat Feb  8 20:23:54 2003
+++ postgresql-7.3.2/src/bin/pg_dump/pg_dump.c    Sat Feb  8 20:25:13 2003
@@ -1355,7 +1355,7 @@
             do
             {
                 cnt = lo_read(g_conn, loFd, buf, loBufSize);
-                if (cnt < 0)
+                if ((int)cnt < 0)
                 {
                     write_msg(NULL, "dumpBlobs(): error reading large object: %s",
                               PQerrorMessage(g_conn));