gst/gstclock.*: Anonymous structs are a gcc (and some other compilers) extension, so don't use them. Since this is on...

Original commit message from CVS:
* gst/gstclock.c: (gst_clock_init), (gst_clock_adjust_unlocked),
(gst_clock_set_rate_offset), (gst_clock_get_rate_offset):
* gst/gstclock.h:
Anonymous structs are a gcc (and some other compilers) extension, so
don't use them. Since this is only for ABI-compatibility, and our
API/ABI freeze is over in a few days, this whole thing will only
last a few days, so don't bother trying to think up a meaningful
name for the struct.