Fix compilation with MSVC by using gst_util_guint64_to_gdouble() and checking for rint() and implementing it ourself ...

Original commit message from CVS:
Based on a patch by: Kwang Yul Seo <kwangyul dot seo at gmail dot com>
* configure.ac:
* ext/cairo/gsttimeoverlay.c:
(gst_cairo_time_overlay_print_smpte_time):
Fix compilation with MSVC by using gst_util_guint64_to_gdouble()
and checking for rint() and implementing it ourself if it doesn't
exist.