Do a g_return_val_if_fail() on err == NULL to be a bit more robuts on

Do a g_return_val_if_fail() on err == NULL to be a bit more robuts on

Fri May 30 15:51:43 2003  Owen Taylor  <otaylor@redhat.com>

        * glib/giochannel.c (g_io_error_get_from_g_error):
        Do a g_return_val_if_fail() on err == NULL to be a
        bit more robuts on buggy IO channel implementations.
        (#113396, Dan Winship)