Use a custom export symbol regex for libgstcheck, as it needs to export symbols that...

Use a custom export symbol regex for libgstcheck, as it needs to export symbols that don't match the standard GStream...

Original commit message from CVS:
* configure.ac:
* libs/gst/check/Makefile.am:
Use a custom export symbol regex for libgstcheck, as it needs
to export symbols that don't match the standard GStreamer gst_*
pattern, and  --export-dynamic is not portable (only works on
GNU ld)
* libs/gst/check/gstcheck.c: (gst_check_setup_src_pad),
(gst_check_setup_sink_pad):
Make sure to pass a message parameter to the fail_* macros.
* tests/check/gst/gstinfo.c: (GST_START_TEST):
Fix some compiler warnings.