Found by Oracle's Parfait 1.2 static analyzer:
   Null pointer dereference (CWE 476): Read from null pointer ext
        at line 322 of /export/alanc/X.Org/amd64-parfait/xcb/xpyb/src/conn.c
            in function 'xpybConn_call'.
          Function xpybConn_load_ext may return constant 'NULL' at line 141,
              called at line 321.
          Null pointer introduced at line 141 in function 'xpybConn_load_ext'.

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>