riff: GST_EXPORT -> GST_RIFF_API

We need different export decorators for the different libs.
For now no actual change though, just rename before the release,
and add prelude headers to define the new decorator to GST_EXPORT.
diff --git a/gst-libs/gst/riff/Makefile.am b/gst-libs/gst/riff/Makefile.am
index 36f62ac..fb53f06 100644
--- a/gst-libs/gst/riff/Makefile.am
+++ b/gst-libs/gst/riff/Makefile.am
@@ -8,6 +8,7 @@
 libgstriff_@GST_API_VERSION@includedir = $(includedir)/gstreamer-@GST_API_VERSION@/gst/riff
 libgstriff_@GST_API_VERSION@include_HEADERS = \
 	riff.h \
+	riff-prelude.h \
 	riff-ids.h \
 	riff-media.h \
 	riff-read.h
diff --git a/gst-libs/gst/riff/meson.build b/gst-libs/gst/riff/meson.build
index b5bd4fa..9662e71 100644
--- a/gst-libs/gst/riff/meson.build
+++ b/gst-libs/gst/riff/meson.build
@@ -6,6 +6,7 @@
 
 riff_headers = [
   'riff.h',
+  'riff-prelude.h',
   'riff-ids.h',
   'riff-media.h',
   'riff-read.h',
diff --git a/gst-libs/gst/riff/riff-ids.h b/gst-libs/gst/riff/riff-ids.h
index cd5a934..5baca98 100644
--- a/gst-libs/gst/riff/riff-ids.h
+++ b/gst-libs/gst/riff/riff-ids.h
@@ -23,6 +23,7 @@
 #define __GST_RIFF_IDS_H__
 
 #include <gst/gst.h>
+#include "riff-prelude.h"
 
 G_BEGIN_DECLS
 
diff --git a/gst-libs/gst/riff/riff-media.h b/gst-libs/gst/riff/riff-media.h
index aa9f9d3..200bee1 100644
--- a/gst-libs/gst/riff/riff-media.h
+++ b/gst-libs/gst/riff/riff-media.h
@@ -32,7 +32,7 @@
  * Create caos. strh/strf, strf/strd_data and codec_name can be NULL.
  */
 
-GST_EXPORT
+GST_RIFF_API
 GstCaps * gst_riff_create_video_caps (guint32              codec_fcc,
                                       gst_riff_strh      * strh,
                                       gst_riff_strf_vids * strf,
@@ -40,7 +40,7 @@
                                       GstBuffer          * strd_data,
                                       char              ** codec_name);
 
-GST_EXPORT
+GST_RIFF_API
 GstCaps * gst_riff_create_audio_caps (guint16              codec_id,
                                       gst_riff_strh      * strh,
                                       gst_riff_strf_auds * strf,
@@ -49,7 +49,7 @@
                                       char              ** codec_name,
                                       gint                 channel_reorder_map[18]);
 
-GST_EXPORT
+GST_RIFF_API
 GstCaps * gst_riff_create_iavs_caps  (guint32              codec_fcc,
                                       gst_riff_strh      * strh,
                                       gst_riff_strf_iavs * strf,
@@ -60,13 +60,13 @@
  * Create template caps (includes all known types).
  */
 
-GST_EXPORT
+GST_RIFF_API
 GstCaps * gst_riff_create_video_template_caps (void);
 
-GST_EXPORT
+GST_RIFF_API
 GstCaps * gst_riff_create_audio_template_caps (void);
 
-GST_EXPORT
+GST_RIFF_API
 GstCaps * gst_riff_create_iavs_template_caps  (void);
 
 G_END_DECLS
diff --git a/gst-libs/gst/riff/riff-prelude.h b/gst-libs/gst/riff/riff-prelude.h
new file mode 100644
index 0000000..fc997a4
--- /dev/null
+++ b/gst-libs/gst/riff/riff-prelude.h
@@ -0,0 +1,31 @@
+/* GStreamer RIFF Library
+ * Copyright (C) 2018 GStreamer developers
+ *
+ * riff-prelude.h: prelude include header for gst-riff library
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __GST_RIFF_PRELUDE_H__
+#define __GST_RIFF_PRELUDE_H__
+
+#include <gst/gst.h>
+
+#ifndef GST_RIFF_API
+#define GST_RIFF_API GST_EXPORT
+#endif
+
+#endif /* __GST_RIFF_PRELUDE_H__ */
diff --git a/gst-libs/gst/riff/riff-read.h b/gst-libs/gst/riff/riff-read.h
index f9a8740..77a768a 100644
--- a/gst-libs/gst/riff/riff-read.h
+++ b/gst-libs/gst/riff/riff-read.h
@@ -33,7 +33,7 @@
  * Operate using pull_range().
  */
 
-GST_EXPORT
+GST_RIFF_API
 GstFlowReturn gst_riff_read_chunk   (GstElement * element,
                                      GstPad     * pad,
                                      guint64    * offset,
@@ -47,42 +47,42 @@
  * by the function.
  */
 
-GST_EXPORT
+GST_RIFF_API
 gboolean gst_riff_parse_chunk       (GstElement * element,
                                      GstBuffer  * buf,
                                      guint      * offset,
                                      guint32    * fourcc,
                                      GstBuffer ** chunk_data);
 
-GST_EXPORT
+GST_RIFF_API
 gboolean gst_riff_parse_file_header (GstElement * element,
                                      GstBuffer  * buf,
                                      guint32    * doctype);
 
-GST_EXPORT
+GST_RIFF_API
 gboolean gst_riff_parse_strh        (GstElement     * element,
                                      GstBuffer      * buf,
                                      gst_riff_strh ** strh);
 
-GST_EXPORT
+GST_RIFF_API
 gboolean gst_riff_parse_strf_vids   (GstElement          * element,
                                      GstBuffer           * buf,
                                      gst_riff_strf_vids ** strf,
                                      GstBuffer          ** data);
 
-GST_EXPORT
+GST_RIFF_API
 gboolean gst_riff_parse_strf_auds   (GstElement          * element,
                                      GstBuffer           * buf,
                                      gst_riff_strf_auds ** strf,
                                      GstBuffer          ** data);
 
-GST_EXPORT
+GST_RIFF_API
 gboolean gst_riff_parse_strf_iavs   (GstElement          * element,
                                      GstBuffer           * buf,
                                      gst_riff_strf_iavs ** strf,
                                      GstBuffer          ** data);
 
-GST_EXPORT
+GST_RIFF_API
 void gst_riff_parse_info            (GstElement  * element,
                                      GstBuffer   * buf,
                                      GstTagList ** taglist);
@@ -90,7 +90,7 @@
  * Init.
  */
 
-GST_EXPORT
+GST_RIFF_API
 void gst_riff_init                  (void);
 
 G_END_DECLS
diff --git a/gst-libs/gst/riff/riff.h b/gst-libs/gst/riff/riff.h
index a4b2205..e610305 100644
--- a/gst-libs/gst/riff/riff.h
+++ b/gst-libs/gst/riff/riff.h
@@ -22,6 +22,7 @@
 #ifndef __GST_RIFF_H__
 #define __GST_RIFF_H__
 
+#include <gst/riff/riff-prelude.h>
 #include <gst/riff/riff-ids.h>
 #include <gst/riff/riff-media.h>
 #include <gst/riff/riff-read.h>