ext/metadata/Makefile.am: Add some relevant variables to CFLAGS and LIBADD, for examp...

ext/metadata/Makefile.am: Add some relevant variables to CFLAGS and LIBADD, for example our compiler warnings paramters.

Original commit message from CVS:
* ext/metadata/Makefile.am:
Add some relevant variables to CFLAGS and LIBADD, for example our
compiler warnings paramters.
* ext/metadata/gstbasemetadata.c:
(gst_base_metadata_strip_push_buffer),
(gst_base_metadata_calculate_offsets),
(gst_base_metadata_src_event), (gst_base_metadata_sink_activate):
* ext/metadata/gstmetadatademux.c: (gst_metadata_demux_init),
(gst_metadata_demux_set_property), (gst_metadata_demux_dispose):
* ext/metadata/gstmetadatamux.c: (gst_metadata_mux_init),
(gst_metadata_mux_set_property), (gst_metadata_mux_get_property),
(gst_metadata_mux_dispose),
(gst_metadata_mux_create_chunks_from_tags):
* ext/metadata/metadata.c: (metadata_dispose):
* ext/metadata/metadataexif.c:
(metadataparse_exif_content_foreach_entry_func),
(metadatamux_exif_for_each_tag_in_list):
* ext/metadata/metadataiptc.c:
(metadatamux_iptc_for_each_tag_in_list):
* ext/metadata/metadatamuxjpeg.c: (metadatamux_jpeg_lazy_update),
(metadatamux_jpeg_reading):
* ext/metadata/metadatamuxpng.c: (metadatamux_png_reading):
* ext/metadata/metadataparsejpeg.c: (metadataparse_jpeg_reading):
* ext/metadata/metadataparsepng.c:
* ext/metadata/metadataparseutil.h:
* ext/metadata/metadataxmp.c: (metadataparse_xmp_tag_list_add),
(metadatamux_xmp_create_chunk_from_tag_list):
Fix a million warnings that showed up after the above change.