net: GST_EXPORT -> GST_NET_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/libs/gst/net/Makefile.am b/libs/gst/net/Makefile.am
index 35ed906..de254e9 100644
--- a/libs/gst/net/Makefile.am
+++ b/libs/gst/net/Makefile.am
@@ -3,6 +3,7 @@
 libgstnet_@GST_API_VERSION@_includedir = $(includedir)/gstreamer-@GST_API_VERSION@/gst/net
 libgstnet_@GST_API_VERSION@_include_HEADERS = \
     net.h \
+    net-prelude.h \
     gstnet.h \
     gstnetaddressmeta.h \
     gstnetclientclock.h \
diff --git a/libs/gst/net/gstnet.h b/libs/gst/net/gstnet.h
index 96cc8b8..2817380 100644
--- a/libs/gst/net/gstnet.h
+++ b/libs/gst/net/gstnet.h
@@ -21,6 +21,8 @@
 #ifndef __GST_NET_H__
 #define __GST_NET_H__
 
+#include <gst/net/net-prelude.h>
+
 #include <gst/net/gstnetaddressmeta.h>
 #include <gst/net/gstnetclientclock.h>
 #include <gst/net/gstnettimepacket.h>
diff --git a/libs/gst/net/gstnetaddressmeta.h b/libs/gst/net/gstnetaddressmeta.h
index e891413..e949b31 100644
--- a/libs/gst/net/gstnetaddressmeta.h
+++ b/libs/gst/net/gstnetaddressmeta.h
@@ -22,6 +22,7 @@
 
 #include <gst/gst.h>
 #include <gio/gio.h>
+#include <gst/net/net-prelude.h>
 
 G_BEGIN_DECLS
 
@@ -40,20 +41,20 @@
   GSocketAddress *addr;
 };
 
-GST_EXPORT
+GST_NET_API
 GType gst_net_address_meta_api_get_type (void);
 #define GST_NET_ADDRESS_META_API_TYPE (gst_net_address_meta_api_get_type())
 
 /* implementation */
 
-GST_EXPORT
+GST_NET_API
 const GstMetaInfo *gst_net_address_meta_get_info (void);
 #define GST_NET_ADDRESS_META_INFO (gst_net_address_meta_get_info())
 
-GST_EXPORT
+GST_NET_API
 GstNetAddressMeta * gst_buffer_add_net_address_meta (GstBuffer      *buffer,
                                                      GSocketAddress *addr);
-GST_EXPORT
+GST_NET_API
 GstNetAddressMeta * gst_buffer_get_net_address_meta (GstBuffer      *buffer);
 
 G_END_DECLS
diff --git a/libs/gst/net/gstnetclientclock.h b/libs/gst/net/gstnetclientclock.h
index 0a9a26c..b741e6b 100644
--- a/libs/gst/net/gstnetclientclock.h
+++ b/libs/gst/net/gstnetclientclock.h
@@ -29,6 +29,7 @@
 
 #include <gst/gst.h>
 #include <gst/gstsystemclock.h>
+#include <gst/net/net-prelude.h>
 
 G_BEGIN_DECLS
 
@@ -68,10 +69,10 @@
   gpointer _gst_reserved[GST_PADDING];
 };
 
-GST_EXPORT
+GST_NET_API
 GType           gst_net_client_clock_get_type	(void);
 
-GST_EXPORT
+GST_NET_API
 GstClock*	gst_net_client_clock_new	(const gchar *name, const gchar *remote_address,
                                                  gint remote_port, GstClockTime base_time);
 
@@ -89,10 +90,10 @@
 typedef struct _GstNetClientClock GstNtpClock;
 typedef struct _GstNetClientClockClass GstNtpClockClass;
 
-GST_EXPORT
+GST_NET_API
 GType           gst_ntp_clock_get_type	        (void);
 
-GST_EXPORT
+GST_NET_API
 GstClock*	gst_ntp_clock_new	        (const gchar *name, const gchar *remote_address,
                                                  gint remote_port, GstClockTime base_time);
 
diff --git a/libs/gst/net/gstnetcontrolmessagemeta.h b/libs/gst/net/gstnetcontrolmessagemeta.h
index 39fe66d..b51b876 100644
--- a/libs/gst/net/gstnetcontrolmessagemeta.h
+++ b/libs/gst/net/gstnetcontrolmessagemeta.h
@@ -22,6 +22,7 @@
 
 #include <gst/gst.h>
 #include <gio/gio.h>
+#include <gst/net/net-prelude.h>
 
 G_BEGIN_DECLS
 
@@ -41,7 +42,7 @@
   GSocketControlMessage *message;
 };
 
-GST_EXPORT
+GST_NET_API
 GType gst_net_control_message_meta_api_get_type (void);
 
 #define GST_NET_CONTROL_MESSAGE_META_API_TYPE \
@@ -52,13 +53,13 @@
 
 /* implementation */
 
-GST_EXPORT
+GST_NET_API
 const GstMetaInfo *gst_net_control_message_meta_get_info (void);
 
 #define GST_NET_CONTROL_MESSAGE_META_INFO \
   (gst_net_control_message_meta_get_info())
 
-GST_EXPORT
+GST_NET_API
 GstNetControlMessageMeta * gst_buffer_add_net_control_message_meta (GstBuffer             * buffer,
                                                                     GSocketControlMessage * message);
 
diff --git a/libs/gst/net/gstnettimepacket.h b/libs/gst/net/gstnettimepacket.h
index 36ceef8..a04ea03 100644
--- a/libs/gst/net/gstnettimepacket.h
+++ b/libs/gst/net/gstnettimepacket.h
@@ -23,6 +23,7 @@
 
 #include <gst/gst.h>
 #include <gio/gio.h>
+#include <gst/net/net-prelude.h>
 
 G_BEGIN_DECLS
 
@@ -47,26 +48,26 @@
   GstClockTime remote_time;
 };
 
-GST_EXPORT
+GST_NET_API
 GType                   gst_net_time_packet_get_type    (void);
 
-GST_EXPORT
+GST_NET_API
 GstNetTimePacket*       gst_net_time_packet_new         (const guint8 *buffer);
 
-GST_EXPORT
+GST_NET_API
 GstNetTimePacket*       gst_net_time_packet_copy        (const GstNetTimePacket *packet);
 
-GST_EXPORT
+GST_NET_API
 void                    gst_net_time_packet_free        (GstNetTimePacket *packet);
 
-GST_EXPORT
+GST_NET_API
 guint8*                 gst_net_time_packet_serialize   (const GstNetTimePacket *packet);
 
-GST_EXPORT
+GST_NET_API
 GstNetTimePacket*	gst_net_time_packet_receive     (GSocket         * socket,
                                                          GSocketAddress ** src_address,
                                                          GError         ** error);
-GST_EXPORT
+GST_NET_API
 gboolean                gst_net_time_packet_send        (const GstNetTimePacket * packet,
                                                          GSocket                * socket,
                                                          GSocketAddress         * dest_address,
diff --git a/libs/gst/net/gstnettimeprovider.h b/libs/gst/net/gstnettimeprovider.h
index 9343306..d1f6de3 100644
--- a/libs/gst/net/gstnettimeprovider.h
+++ b/libs/gst/net/gstnettimeprovider.h
@@ -24,6 +24,7 @@
 #define __GST_NET_TIME_PROVIDER_H__
 
 #include <gst/gst.h>
+#include <gst/net/net-prelude.h>
 
 G_BEGIN_DECLS
 
@@ -62,10 +63,10 @@
   gpointer _gst_reserved[GST_PADDING];
 };
 
-GST_EXPORT
+GST_NET_API
 GType                   gst_net_time_provider_get_type  (void);
 
-GST_EXPORT
+GST_NET_API
 GstNetTimeProvider*     gst_net_time_provider_new       (GstClock *clock,
                                                          const gchar *address,
                                                          gint port);
diff --git a/libs/gst/net/gstptpclock.h b/libs/gst/net/gstptpclock.h
index 6a1c839..06ca5cf 100644
--- a/libs/gst/net/gstptpclock.h
+++ b/libs/gst/net/gstptpclock.h
@@ -23,6 +23,7 @@
 
 #include <gst/gst.h>
 #include <gst/gstsystemclock.h>
+#include <gst/net/net-prelude.h>
 
 G_BEGIN_DECLS
 
@@ -75,19 +76,19 @@
  */
 #define GST_PTP_CLOCK_ID_NONE ((guint64) -1)
 
-GST_EXPORT
+GST_NET_API
 GType           gst_ptp_clock_get_type             (void);
 
-GST_EXPORT
+GST_NET_API
 gboolean        gst_ptp_is_supported               (void);
 
-GST_EXPORT
+GST_NET_API
 gboolean        gst_ptp_is_initialized             (void);
 
-GST_EXPORT
+GST_NET_API
 gboolean        gst_ptp_init                       (guint64 clock_id,
                                                     gchar ** interfaces);
-GST_EXPORT
+GST_NET_API
 void            gst_ptp_deinit                     (void);
 
 #define GST_PTP_STATISTICS_NEW_DOMAIN_FOUND           "GstPtpStatisticsNewDomainFound"
@@ -142,13 +143,13 @@
 typedef gboolean  (*GstPtpStatisticsCallback)      (guint8 domain,
                                                     const GstStructure * stats,
                                                     gpointer user_data);
-GST_EXPORT
+GST_NET_API
 gulong          gst_ptp_statistics_callback_add    (GstPtpStatisticsCallback callback,
                                                     gpointer user_data, GDestroyNotify destroy_data);
-GST_EXPORT
+GST_NET_API
 void            gst_ptp_statistics_callback_remove (gulong id);
 
-GST_EXPORT
+GST_NET_API
 GstClock*       gst_ptp_clock_new                  (const gchar *name,
                                                     guint domain);
 
diff --git a/libs/gst/net/meson.build b/libs/gst/net/meson.build
index c32bef2..0a76fd2 100644
--- a/libs/gst/net/meson.build
+++ b/libs/gst/net/meson.build
@@ -17,6 +17,7 @@
  'gstnettimepacket.h',
  'gstnettimeprovider.h',
  'gstptpclock.h',
+ 'net-prelude.h',
  'net.h',
 ]
 install_headers(gst_net_headers, subdir : 'gstreamer-1.0/gst/net/')
diff --git a/libs/gst/net/net-prelude.h b/libs/gst/net/net-prelude.h
new file mode 100644
index 0000000..8db7565
--- /dev/null
+++ b/libs/gst/net/net-prelude.h
@@ -0,0 +1,31 @@
+/* GStreamer Net Library
+ * Copyright (C) 2018 GStreamer developers
+ *
+ * net-prelude.h: prelude include header for gst-net 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_NET_PRELUDE_H__
+#define __GST_NET_PRELUDE_H__
+
+#include <gst/gst.h>
+
+#ifndef GST_NET_API
+#define GST_NET_API GST_EXPORT
+#endif
+
+#endif /* __GST_NET_PRELUDE_H__ */
diff --git a/libs/gst/net/net.h b/libs/gst/net/net.h
index 8af032e..abecd32 100644
--- a/libs/gst/net/net.h
+++ b/libs/gst/net/net.h
@@ -22,6 +22,8 @@
 #ifndef __GST_NET__H__
 #define __GST_NET__H__
 
+#include <gst/net/net-prelude.h>
+
 #include <gst/net/gstnet.h>
 #include <gst/net/gstnetaddressmeta.h>
 #include <gst/net/gstnetclientclock.h>