libs: fix API export/import and 'inconsistent linkage' on MSVC

For each lib we build export its own API in headers when we're
building it, otherwise import the API from the headers.

This fixes linker warnings on Windows when building with MSVC.

The problem was that we had defined all GST_*_API decorators
unconditionally to GST_EXPORT. This was intentional and only
supposed to be temporary, but caused linker warnings because
we tell the linker that we want to export all symbols even
those from externall DLLs, and when the linker notices that
they were in external DLLS and not present locally it warns.

What we need to do when building each library is: export
the library's own symbols and import all other symbols. To
this end we define e.g. BUILDING_GST_FOO and then we define
the GST_FOO_API decorator either to export or to import
symbols depending on whether BUILDING_GST_FOO is set or not.
That way external users of each library API automatically
get the import.

While we're at it, add new GST_API_EXPORT in config.h and use
that for GST_*_API decorators instead of GST_EXPORT.

The right export define depends on the toolchain and whether
we're using -fvisibility=hidden or not, so it's better to set it
to the right thing directly than hard-coding a compiler whitelist
in the public header.

We put the export define into config.h instead of passing it via the
command line to the compiler because it might contain spaces and brackets
and in the autotools scenario we'd have to pass that through multiple
layers of plumbing and Makefile/shell escaping and we're just not going
to be *that* lucky.

The export define is only used if we're compiling our lib, not by external
users of the lib headers, so it's not a problem to put it into config.h

Also, this means all .c files of libs need to include config.h
to get the export marker defined, so fix up a few that didn't
include config.h.

This commit depends on a common submodule commit that makes gst-glib-gen.mak
add an #include "config.h" to generated enum/marshal .c files for the
autotools build.

https://bugzilla.gnome.org/show_bug.cgi?id=797185

67 files changed, 186 insertions, 36 deletions

diff --git a/common b/common
-Subproject ed78bee437dcbe22e6eef0031d9a29d157c0461
+Subproject cd1dee06bf07f094677d0cf3eea4a2e8c2636b2
diff --git a/configure.ac b/configure.ac
index 326db3be7..1a27f917d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2485,7 +2485,13 @@ fi
 AC_SUBST(DEPRECATED_CFLAGS)
 
 VISIBILITY_CFLAGS=""
-AS_COMPILER_FLAG([-fvisibility=hidden], [VISIBILITY_CFLAGS="-fvisibility=hidden"])
+AS_COMPILER_FLAG([-fvisibility=hidden], [
+  VISIBILITY_CFLAGS="-fvisibility=hidden"
+  AC_DEFINE(GST_API_EXPORT, [extern __attribute__ ((visibility ("default")))], [public symbol export define])
+], [
+  VISIBILITY_CFLAGS=""
+  AC_DEFINE(GST_API_EXPORT, [extern], [public symbol export define])
+])
 AC_SUBST(VISIBILITY_CFLAGS)
 
 VISIBILITY_CXXFLAGS=""
diff --git a/gst-libs/gst/adaptivedemux/Makefile.am b/gst-libs/gst/adaptivedemux/Makefile.am
index 2af05173a..05b2198c1 100644
--- a/gst-libs/gst/adaptivedemux/Makefile.am
+++ b/gst-libs/gst/adaptivedemux/Makefile.am
@@ -14,6 +14,7 @@ libgstadaptivedemux_@GST_API_VERSION@_la_CFLAGS = \
 	$(GST_PLUGINS_BAD_CFLAGS) \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	-DGST_USE_UNSTABLE_API \
+	-DBUILDING_GST_ADAPTIVE_DEMUX \
 	$(GST_CFLAGS)
 libgstadaptivedemux_@GST_API_VERSION@_la_LIBADD = \
 	$(top_builddir)/gst-libs/gst/uridownloader/libgsturidownloader-$(GST_API_VERSION).la \
diff --git a/gst-libs/gst/adaptivedemux/adaptive-demux-prelude.h b/gst-libs/gst/adaptivedemux/adaptive-demux-prelude.h
index 402a78fa5..04104cffe 100644
--- a/gst-libs/gst/adaptivedemux/adaptive-demux-prelude.h
+++ b/gst-libs/gst/adaptivedemux/adaptive-demux-prelude.h
@@ -25,7 +25,11 @@
 #include <gst/gst.h>
 
 #ifndef GST_ADAPTIVE_DEMUX_API
-#define GST_ADAPTIVE_DEMUX_API GST_EXPORT
+# ifdef BUILDING_GST_ADAPTIVE_DEMUX
+#  define GST_ADAPTIVE_DEMUX_API GST_API_EXPORT         /* from config.h */
+# else
+#  define GST_ADAPTIVE_DEMUX_API GST_API_IMPORT
+# endif
 #endif
 
 #endif /* __GST_ADAPTIVE_DEMUX_PRELUDE_H__ */
diff --git a/gst-libs/gst/adaptivedemux/meson.build b/gst-libs/gst/adaptivedemux/meson.build
index 5f8eac32d..de64a271b 100644
--- a/gst-libs/gst/adaptivedemux/meson.build
+++ b/gst-libs/gst/adaptivedemux/meson.build
@@ -1,6 +1,6 @@
 gstadaptivedemux = library('gstadaptivedemux-' + api_version,
   'gstadaptivedemux.c',
-  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API'],
+  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API', '-DBUILDING_GST_ADAPTIVE_DEMUX'],
   include_directories : [configinc, libsinc],
   version : libversion,
   soversion : soversion,
diff --git a/gst-libs/gst/audio/Makefile.am b/gst-libs/gst/audio/Makefile.am
index 0ad482d71..6615bfc89 100644
--- a/gst-libs/gst/audio/Makefile.am
+++ b/gst-libs/gst/audio/Makefile.am
@@ -11,6 +11,7 @@ nodist_libgstbadaudio_@GST_API_VERSION@_la_SOURCES = $(BUILT_SOURCES)
 
 libgstbadaudio_@GST_API_VERSION@_la_CFLAGS = \
 	-DGST_USE_UNSTABLE_API \
+	-DBUILDING_GST_AUDIO_BAD \
 	-I$(top_srcdir)/gst-libs \
 	-I$(top_builddir)/gst-libs \
 	$(GST_CFLAGS) $(ORC_CFLAGS) \
diff --git a/gst-libs/gst/audio/audio-bad-prelude.h b/gst-libs/gst/audio/audio-bad-prelude.h
index 71b326c33..ceb4d9515 100644
--- a/gst-libs/gst/audio/audio-bad-prelude.h
+++ b/gst-libs/gst/audio/audio-bad-prelude.h
@@ -25,7 +25,11 @@
 #include <gst/gst.h>
 
 #ifndef GST_AUDIO_BAD_API
-#define GST_AUDIO_BAD_API GST_EXPORT
+# ifdef BUILDING_GST_AUDIO_BAD
+#  define GST_AUDIO_BAD_API GST_API_EXPORT         /* from config.h */
+# else
+#  define GST_AUDIO_BAD_API GST_API_IMPORT
+# endif
 #endif
 
 #endif /* __GST_AUDIO_BAD_PRELUDE_H__ */
diff --git a/gst-libs/gst/audio/gstplanaraudioadapter.c b/gst-libs/gst/audio/gstplanaraudioadapter.c
index 87a4f128b..758c1c925 100644
--- a/gst-libs/gst/audio/gstplanaraudioadapter.c
+++ b/gst-libs/gst/audio/gstplanaraudioadapter.c
@@ -27,6 +27,9 @@
  * non-interleaved (planar) audio buffers. Before using, an audio format
  * must be configured with gst_planar_audio_adapter_configure()
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include "gstplanaraudioadapter.h"
 
diff --git a/gst-libs/gst/audio/meson.build b/gst-libs/gst/audio/meson.build
index b8b7bd592..b0f11a72a 100644
--- a/gst-libs/gst/audio/meson.build
+++ b/gst-libs/gst/audio/meson.build
@@ -5,7 +5,7 @@ install_headers(badaudio_headers, subdir : 'gstreamer-1.0/gst/audio')
 
 gstbadaudio = library('gstbadaudio-' + api_version,
   badaudio_sources,
-  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API'],
+  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API', '-DBUILDING_GST_AUDIO_BAD'],
   include_directories : [configinc, libsinc],
   version : libversion,
   soversion : soversion,
diff --git a/gst-libs/gst/basecamerabinsrc/Makefile.am b/gst-libs/gst/basecamerabinsrc/Makefile.am
index 5c68f0fbb..3a669ad62 100644
--- a/gst-libs/gst/basecamerabinsrc/Makefile.am
+++ b/gst-libs/gst/basecamerabinsrc/Makefile.am
@@ -19,6 +19,7 @@ libgstbasecamerabinsrc_@GST_API_VERSION@_la_CFLAGS = \
 	$(GST_PLUGINS_BAD_CFLAGS) \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	-DGST_USE_UNSTABLE_API \
+	-DBUILDING_GST_BASE_CAMERA_BIN_SRC \
 	$(GST_CFLAGS)
 libgstbasecamerabinsrc_@GST_API_VERSION@_la_LIBADD = \
 	-lgstapp-$(GST_API_VERSION) $(GST_PLUGINS_BASE_LIBS) $(GST_BASE_LIBS) $(GST_LIBS)
diff --git a/gst-libs/gst/basecamerabinsrc/basecamerabinsrc-prelude.h b/gst-libs/gst/basecamerabinsrc/basecamerabinsrc-prelude.h
index 6dc1477e1..ec9a76608 100644
--- a/gst-libs/gst/basecamerabinsrc/basecamerabinsrc-prelude.h
+++ b/gst-libs/gst/basecamerabinsrc/basecamerabinsrc-prelude.h
@@ -25,7 +25,11 @@
 #include <gst/gst.h>
 
 #ifndef GST_BASE_CAMERA_BIN_SRC_API
-#define GST_BASE_CAMERA_BIN_SRC_API GST_EXPORT
+# ifdef BUILDING_GST_BASE_CAMERA_BIN_SRC
+#  define GST_BASE_CAMERA_BIN_SRC_API GST_API_EXPORT         /* from config.h */
+# else
+#  define GST_BASE_CAMERA_BIN_SRC_API GST_API_IMPORT
+# endif
 #endif
 
 #endif /* __GST_BASE_CAMERA_BIN_SRC_PRELUDE_H__ */
diff --git a/gst-libs/gst/basecamerabinsrc/gstcamerabin-enum.c b/gst-libs/gst/basecamerabinsrc/gstcamerabin-enum.c
index bd9088c94..f55680627 100644
--- a/gst-libs/gst/basecamerabinsrc/gstcamerabin-enum.c
+++ b/gst-libs/gst/basecamerabinsrc/gstcamerabin-enum.c
@@ -17,6 +17,9 @@
  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include "gstcamerabin-enum.h"
 
diff --git a/gst-libs/gst/basecamerabinsrc/gstcamerabinpreview.c b/gst-libs/gst/basecamerabinsrc/gstcamerabinpreview.c
index 48ec2fec8..6d8545f12 100644
--- a/gst-libs/gst/basecamerabinsrc/gstcamerabinpreview.c
+++ b/gst-libs/gst/basecamerabinsrc/gstcamerabinpreview.c
@@ -26,6 +26,10 @@
  * #GstCameraBinVideo.
  *
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
 #include <gst/app/gstappsrc.h>
 #include <gst/app/gstappsink.h>
 #include <gst/glib-compat-private.h>
diff --git a/gst-libs/gst/basecamerabinsrc/meson.build b/gst-libs/gst/basecamerabinsrc/meson.build
index b1ba10689..830e9157a 100644
--- a/gst-libs/gst/basecamerabinsrc/meson.build
+++ b/gst-libs/gst/basecamerabinsrc/meson.build
@@ -13,7 +13,7 @@ install_headers(camerabin_headers, subdir : 'gstreamer-1.0/gst/basecamerabinsrc'
 
 gstbasecamerabin = library('gstbasecamerabinsrc-' + api_version,
   camerabin_sources,
-  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API'],
+  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API', '-DBUILDING_GST_BASE_CAMERA_BIN_SRC'],
   include_directories : [configinc, libsinc],
   version : libversion,
   soversion : soversion,
diff --git a/gst-libs/gst/codecparsers/Makefile.am b/gst-libs/gst/codecparsers/Makefile.am
index 47ad21d21..081deead2 100644
--- a/gst-libs/gst/codecparsers/Makefile.am
+++ b/gst-libs/gst/codecparsers/Makefile.am
@@ -26,6 +26,7 @@ libgstcodecparsers_@GST_API_VERSION@include_HEADERS = \
 libgstcodecparsers_@GST_API_VERSION@_la_CFLAGS = \
 	$(GST_PLUGINS_BAD_CFLAGS) \
 	-DGST_USE_UNSTABLE_API \
+	-DBUILDING_GST_CODEC_PARSERS \
 	$(GST_CFLAGS) \
 	-Dvp8_norm=gst_codecparsers_vp8_norm \
 	-Dvp8dx_start_decode=gst_codecparsers_vp8dx_start_decode \
diff --git a/gst-libs/gst/codecparsers/codecparsers-prelude.h b/gst-libs/gst/codecparsers/codecparsers-prelude.h
index 6fe11d304..b056c6489 100644
--- a/gst-libs/gst/codecparsers/codecparsers-prelude.h
+++ b/gst-libs/gst/codecparsers/codecparsers-prelude.h
@@ -25,7 +25,11 @@
 #include <gst/gst.h>
 
 #ifndef GST_CODEC_PARSERS_API
-#define GST_CODEC_PARSERS_API GST_EXPORT
+# ifdef BUILDING_GST_CODEC_PARSERS
+#  define GST_CODEC_PARSERS_API GST_API_EXPORT         /* from config.h */
+# else
+#  define GST_CODEC_PARSERS_API GST_API_IMPORT
+# endif
 #endif
 
 #endif /* __GST_CODEC_PARSERS_PRELUDE_H__ */
diff --git a/gst-libs/gst/codecparsers/dboolhuff.c b/gst-libs/gst/codecparsers/dboolhuff.c
index 692d78be6..15e6c7cf3 100644
--- a/gst-libs/gst/codecparsers/dboolhuff.c
+++ b/gst-libs/gst/codecparsers/dboolhuff.c
@@ -7,7 +7,9 @@
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
-
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include "dboolhuff.h"
 
diff --git a/gst-libs/gst/codecparsers/gstjpeg2000sampling.c b/gst-libs/gst/codecparsers/gstjpeg2000sampling.c
index 543282d49..526a7ecce 100644
--- a/gst-libs/gst/codecparsers/gstjpeg2000sampling.c
+++ b/gst-libs/gst/codecparsers/gstjpeg2000sampling.c
@@ -24,6 +24,9 @@
  * @short_description: Manage JPEG 2000 sampling and colorspace fields
  *
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include "gstjpeg2000sampling.h"
 
diff --git a/gst-libs/gst/codecparsers/gstjpegparser.c b/gst-libs/gst/codecparsers/gstjpegparser.c
index bbc1f181e..64110763f 100644
--- a/gst-libs/gst/codecparsers/gstjpegparser.c
+++ b/gst-libs/gst/codecparsers/gstjpegparser.c
@@ -26,6 +26,9 @@
  * Provides useful functions for parsing JPEG images
  *
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include <string.h>
 #include <stdlib.h>
diff --git a/gst-libs/gst/codecparsers/gstvp8rangedecoder.c b/gst-libs/gst/codecparsers/gstvp8rangedecoder.c
index 4d381c5a7..9bf1035f9 100644
--- a/gst-libs/gst/codecparsers/gstvp8rangedecoder.c
+++ b/gst-libs/gst/codecparsers/gstvp8rangedecoder.c
@@ -7,6 +7,9 @@
  * in the file PATENTS.  All contributing project authors may
  * be found in the AUTHORS file in the root of the source tree.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include "gstvp8rangedecoder.h"
 #include "dboolhuff.h"
diff --git a/gst-libs/gst/codecparsers/meson.build b/gst-libs/gst/codecparsers/meson.build
index 12168ec53..c08803db2 100644
--- a/gst-libs/gst/codecparsers/meson.build
+++ b/gst-libs/gst/codecparsers/meson.build
@@ -34,6 +34,7 @@ install_headers(codecparser_headers, subdir : 'gstreamer-1.0/gst/codecparsers')
 
 cp_args = [
   '-DGST_USE_UNSTABLE_API',
+  '-DBUILDING_GST_CODEC_PARSERS',
   '-Dvp8_norm=gst_codecparsers_vp8_norm',
   '-Dvp8dx_start_decode=gst_codecparsers_vp8dx_start_decode',
   '-Dvp8dx_bool_decoder_fill=gst_codecparsers_vp8dx_bool_decoder_fill',
diff --git a/gst-libs/gst/codecparsers/parserutils.c b/gst-libs/gst/codecparsers/parserutils.c
index d4a3f40ce..098f43644 100644
--- a/gst-libs/gst/codecparsers/parserutils.c
+++ b/gst-libs/gst/codecparsers/parserutils.c
@@ -18,6 +18,9 @@
  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include "parserutils.h"
 
diff --git a/gst-libs/gst/codecparsers/vp8utils.c b/gst-libs/gst/codecparsers/vp8utils.c
index c2e7d238c..2905beb0f 100644
--- a/gst-libs/gst/codecparsers/vp8utils.c
+++ b/gst-libs/gst/codecparsers/vp8utils.c
@@ -7,6 +7,9 @@
  * in the file PATENTS.  All contributing project authors may
  * be found in the AUTHORS file in the root of the source tree.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include <string.h>
 #include "vp8utils.h"
diff --git a/gst-libs/gst/insertbin/Makefile.am b/gst-libs/gst/insertbin/Makefile.am
index 330af8338..57b24a114 100644
--- a/gst-libs/gst/insertbin/Makefile.am
+++ b/gst-libs/gst/insertbin/Makefile.am
@@ -9,6 +9,7 @@ libgstinsertbin_@GST_API_VERSION@include_HEADERS = gstinsertbin.h
 
 libgstinsertbin_@GST_API_VERSION@_la_CFLAGS = \
 	$(GST_PLUGINS_BAD_CFLAGS) \
+	-DBUILDING_GST_INSERT_BIN \
 	$(GST_CFLAGS)
 
 libgstinsertbin_@GST_API_VERSION@_la_LIBADD = \
diff --git a/gst-libs/gst/insertbin/gstinsertbin.h b/gst-libs/gst/insertbin/gstinsertbin.h
index d5539a405..705ae309c 100644
--- a/gst-libs/gst/insertbin/gstinsertbin.h
+++ b/gst-libs/gst/insertbin/gstinsertbin.h
@@ -34,7 +34,11 @@
 #include <gst/gst.h>
 
 #ifndef GST_INSERT_BIN_API
-#define GST_INSERT_BIN_API GST_EXPORT
+# ifdef BUILDING_GST_INSERT_BIN
+#  define GST_INSERT_BIN_API GST_API_EXPORT         /* from config.h */
+# else
+#  define GST_INSERT_BIN_API GST_API_IMPORT
+# endif
 #endif
 
 G_BEGIN_DECLS
diff --git a/gst-libs/gst/insertbin/meson.build b/gst-libs/gst/insertbin/meson.build
index 8c9e1f5a8..ac8f2b350 100644
--- a/gst-libs/gst/insertbin/meson.build
+++ b/gst-libs/gst/insertbin/meson.build
@@ -4,7 +4,7 @@ install_headers(insert_headers, subdir : 'gstreamer-1.0/gst/insertbin')
 
 gstinsertbin = library('gstinsertbin-' + api_version,
   insert_sources,
-  c_args : gst_plugins_bad_args + [ '-DGST_USE_UNSTABLE_API' ],
+  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API', '-DBUILDING_GST_INSERT_BIN'],
   include_directories : [configinc, libsinc],
   version : libversion,
   soversion : soversion,
diff --git a/gst-libs/gst/interfaces/Makefile.am b/gst-libs/gst/interfaces/Makefile.am
index de9d2a664..660853ab1 100644
--- a/gst-libs/gst/interfaces/Makefile.am
+++ b/gst-libs/gst/interfaces/Makefile.am
@@ -34,6 +34,7 @@ nodist_libgstphotography_@GST_API_VERSION@_la_SOURCES = 	\
 
 libgstphotography_@GST_API_VERSION@_la_CFLAGS = \
 	-DGST_USE_UNSTABLE_API \
+	-DBUILDING_GST_PHOTOGRAPHY \
 	$(GST_PLUGINS_BAD_CFLAGS) \
 	$(GST_CFLAGS)
 libgstphotography_@GST_API_VERSION@_la_LIBADD = $(GST_LIBS) 
diff --git a/gst-libs/gst/interfaces/meson.build b/gst-libs/gst/interfaces/meson.build
index 4e2fb4305..52284715b 100644
--- a/gst-libs/gst/interfaces/meson.build
+++ b/gst-libs/gst/interfaces/meson.build
@@ -4,6 +4,7 @@ install_headers(photo_headers, subdir : 'gstreamer-1.0/gst/interfaces')
 
 photo_enums = gnome.mkenums_simple('photography-enumtypes',
   sources : photo_headers,
+  body_prefix : '#ifdef HAVE_CONFIG_H\n#include "config.h"\n#endif',
   header_prefix : '#include <gst/interfaces/photography-prelude.h>',
   decorator: 'GST_PHOTOGRAPHY_API',
   install_header: true,
@@ -14,7 +15,7 @@ photoenum_h = photo_enums[1]
 
 gstphotography = library('gstphotography-' + api_version,
   photography_sources, photoenum_h, photoenum_c,
-  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API'],
+  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API', '-DBUILDING_GST_PHOTOGRAPHY'],
   include_directories : [configinc, libsinc],
   version : libversion,
   soversion : soversion,
diff --git a/gst-libs/gst/interfaces/photography-prelude.h b/gst-libs/gst/interfaces/photography-prelude.h
index 7e300e60a..dbb7f13f9 100644
--- a/gst-libs/gst/interfaces/photography-prelude.h
+++ b/gst-libs/gst/interfaces/photography-prelude.h
@@ -25,7 +25,11 @@
 #include <gst/gst.h>
 
 #ifndef GST_PHOTOGRAPHY_API
-#define GST_PHOTOGRAPHY_API GST_EXPORT
+# ifdef BUILDING_GST_PHOTOGRAPHY
+#  define GST_PHOTOGRAPHY_API GST_API_EXPORT         /* from config.h */
+# else
+#  define GST_PHOTOGRAPHY_API GST_API_IMPORT
+# endif
 #endif
 
 #endif /* __GST_PHOTOGRAPHY_PRELUDE_H__ */
diff --git a/gst-libs/gst/isoff/Makefile.am b/gst-libs/gst/isoff/Makefile.am
index b99acaed6..a375089ab 100644
--- a/gst-libs/gst/isoff/Makefile.am
+++ b/gst-libs/gst/isoff/Makefile.am
@@ -12,6 +12,7 @@ libgstisoff_@GST_API_VERSION@include_HEADERS = \
 libgstisoff_@GST_API_VERSION@_la_CFLAGS = \
 	$(GST_PLUGINS_BAD_CFLAGS) \
 	-DGST_USE_UNSTABLE_API \
+	-DBUILDING_GST_ISOFF \
 	$(GST_CFLAGS)
 
 libgstisoff_@GST_API_VERSION@_la_LIBADD = \
diff --git a/gst-libs/gst/isoff/gstisoff.c b/gst-libs/gst/isoff/gstisoff.c
index e6f0cfbcb..56e2a064d 100644
--- a/gst-libs/gst/isoff/gstisoff.c
+++ b/gst-libs/gst/isoff/gstisoff.c
@@ -21,6 +21,9 @@
  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  * Boston, MA 02111-1307, USA.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include "gstisoff.h"
 #include <gst/base/gstbytereader.h>
diff --git a/gst-libs/gst/isoff/gstisoff.h b/gst-libs/gst/isoff/gstisoff.h
index 437859b2e..43d337516 100644
--- a/gst-libs/gst/isoff/gstisoff.h
+++ b/gst-libs/gst/isoff/gstisoff.h
@@ -31,7 +31,11 @@
 G_BEGIN_DECLS
 
 #ifndef GST_ISOFF_API
-#define GST_ISOFF_API GST_EXPORT
+# ifdef BUILDING_GST_ISOFF
+#  define GST_ISOFF_API GST_API_EXPORT         /* from config.h */
+# else
+#  define GST_ISOFF_API GST_API_IMPORT
+# endif
 #endif
 
 typedef enum {
diff --git a/gst-libs/gst/isoff/meson.build b/gst-libs/gst/isoff/meson.build
index d468a5a67..4cb75426c 100644
--- a/gst-libs/gst/isoff/meson.build
+++ b/gst-libs/gst/isoff/meson.build
@@ -8,7 +8,7 @@ install_headers(isoff_headers, subdir : 'gstreamer-1.0/gst/isoff')
 
 gstisoff = library('gstisoff-' + api_version,
   isoff_sources,
-  c_args : gst_plugins_bad_args + [ '-DGST_USE_UNSTABLE_API' ],
+  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API', '-DBUILDING_GST_ISOFF'],
   include_directories : [configinc, libsinc],
   version : libversion,
   soversion : soversion,
diff --git a/gst-libs/gst/mpegts/Makefile.am b/gst-libs/gst/mpegts/Makefile.am
index 70498209b..59a3ddd4b 100644
--- a/gst-libs/gst/mpegts/Makefile.am
+++ b/gst-libs/gst/mpegts/Makefile.am
@@ -28,6 +28,7 @@ nodist_libgstmpegts_@GST_API_VERSION@include_HEADERS = \
 libgstmpegts_@GST_API_VERSION@_la_CFLAGS = \
 	$(GST_PLUGINS_BAD_CFLAGS) \
 	-DGST_USE_UNSTABLE_API \
+	-DBUILDING_GST_MPEGTS \
 	$(GST_CFLAGS)
 
 libgstmpegts_@GST_API_VERSION@_la_LIBADD = \
diff --git a/gst-libs/gst/mpegts/gst-atsc-section.c b/gst-libs/gst/mpegts/gst-atsc-section.c
index 753254895..a67863f8b 100644
--- a/gst-libs/gst/mpegts/gst-atsc-section.c
+++ b/gst-libs/gst/mpegts/gst-atsc-section.c
@@ -19,6 +19,9 @@
  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include <string.h>
 #include <stdlib.h>
diff --git a/gst-libs/gst/mpegts/gst-dvb-descriptor.c b/gst-libs/gst/mpegts/gst-dvb-descriptor.c
index 8410a898f..bd8a069b5 100644
--- a/gst-libs/gst/mpegts/gst-dvb-descriptor.c
+++ b/gst-libs/gst/mpegts/gst-dvb-descriptor.c
@@ -20,6 +20,10 @@
  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
 #include <stdlib.h>
 #include <string.h>
 
diff --git a/gst-libs/gst/mpegts/gst-dvb-section.c b/gst-libs/gst/mpegts/gst-dvb-section.c
index 46fc63449..58f71f610 100644
--- a/gst-libs/gst/mpegts/gst-dvb-section.c
+++ b/gst-libs/gst/mpegts/gst-dvb-section.c
@@ -28,6 +28,9 @@
  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include <string.h>
 #include <stdlib.h>
diff --git a/gst-libs/gst/mpegts/gstmpegtsdescriptor.c b/gst-libs/gst/mpegts/gstmpegtsdescriptor.c
index 588413239..a553c9493 100644
--- a/gst-libs/gst/mpegts/gstmpegtsdescriptor.c
+++ b/gst-libs/gst/mpegts/gstmpegtsdescriptor.c
@@ -20,6 +20,10 @@
  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
 #include <stdlib.h>
 #include <string.h>
 
diff --git a/gst-libs/gst/mpegts/gstmpegtssection.c b/gst-libs/gst/mpegts/gstmpegtssection.c
index 62657da61..41c970ac1 100644
--- a/gst-libs/gst/mpegts/gstmpegtssection.c
+++ b/gst-libs/gst/mpegts/gstmpegtssection.c
@@ -28,6 +28,9 @@
  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include <string.h>
 #include <stdlib.h>
diff --git a/gst-libs/gst/mpegts/meson.build b/gst-libs/gst/mpegts/meson.build
index 6c3758e0a..f017e86a0 100644
--- a/gst-libs/gst/mpegts/meson.build
+++ b/gst-libs/gst/mpegts/meson.build
@@ -20,6 +20,7 @@ install_headers(mpegts_headers, subdir : 'gstreamer-1.0/gst/mpegts')
 
 mpegts_enums = gnome.mkenums_simple('gstmpegts-enumtypes',
   sources : mpegts_headers,
+  body_prefix : '#ifdef HAVE_CONFIG_H\n#include "config.h"\n#endif',
   header_prefix : '#include <gst/mpegts/mpegts-prelude.h>',
   decorator : 'GST_MPEGTS_API',
   install_header: true,
@@ -31,7 +32,7 @@ gen_sources = [mpegtsenumtypes_h]
 
 gstmpegts = library('gstmpegts-' + api_version,
   mpegts_sources, mpegts_enums,
-  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API'],
+  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API', '-DBUILDING_GST_MPEGTS'],
   include_directories : [configinc, libsinc],
   version : libversion,
   soversion : soversion,
diff --git a/gst-libs/gst/mpegts/mpegts-prelude.h b/gst-libs/gst/mpegts/mpegts-prelude.h
index 26c00a4b1..2b66e26d9 100644
--- a/gst-libs/gst/mpegts/mpegts-prelude.h
+++ b/gst-libs/gst/mpegts/mpegts-prelude.h
@@ -25,7 +25,11 @@
 #include <gst/gst.h>
 
 #ifndef GST_MPEGTS_API
-#define GST_MPEGTS_API GST_EXPORT
+# ifdef BUILDING_GST_MPEGTS
+#  define GST_MPEGTS_API GST_API_EXPORT         /* from config.h */
+# else
+#  define GST_MPEGTS_API GST_API_IMPORT
+# endif
 #endif
 
 #endif /* __GST_MPEGTS_PRELUDE_H__ */
diff --git a/gst-libs/gst/opencv/Makefile.am b/gst-libs/gst/opencv/Makefile.am
index cc0d67f44..5c36a92b7 100644
--- a/gst-libs/gst/opencv/Makefile.am
+++ b/gst-libs/gst/opencv/Makefile.am
@@ -7,6 +7,7 @@ libgstopencv_@GST_API_VERSION@_la_SOURCES = \
 libgstopencv_@GST_API_VERSION@_la_CXXFLAGS = \
 	$(GST_PLUGINS_BAD_CFLAGS) \
 	$(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CXXFLAGS) \
+	-DBUILDING_GST_OPENCV \
 	$(OPENCV_CFLAGS)
 
 libgstopencv_@GST_API_VERSION@_la_LIBADD = $(GST_LIBS) $(GST_BASE_LIBS) \
diff --git a/gst-libs/gst/opencv/meson.build b/gst-libs/gst/opencv/meson.build
index 848aac4b3..2babdec85 100644
--- a/gst-libs/gst/opencv/meson.build
+++ b/gst-libs/gst/opencv/meson.build
@@ -13,7 +13,7 @@ opencv_dep = dependency('opencv', version : '>= 3.0.0', required : get_option('o
 if opencv_dep.found()
   gstopencv = library('gstopencv-' + api_version,
     opencv_sources,
-    c_args : gst_plugins_bad_args,
+    c_args : gst_plugins_bad_args + ['-DBUILDING_GST_OPENCV'],
     include_directories : [configinc, libsinc],
     version : libversion,
     soversion : soversion,
diff --git a/gst-libs/gst/opencv/opencv-prelude.h b/gst-libs/gst/opencv/opencv-prelude.h
index 2cbea56f9..fe719d48f 100644
--- a/gst-libs/gst/opencv/opencv-prelude.h
+++ b/gst-libs/gst/opencv/opencv-prelude.h
@@ -25,7 +25,11 @@
 #include <gst/gst.h>
 
 #ifndef GST_OPENCV_API
-#define GST_OPENCV_API GST_EXPORT
+# ifdef BUILDING_GST_OPENCV
+#  define GST_OPENCV_API GST_API_EXPORT         /* from config.h */
+# else
+#  define GST_OPENCV_API GST_API_IMPORT
+# endif
 #endif
 
 #endif /* __GST_OPENCV_PRELUDE_H__ */
diff --git a/gst-libs/gst/player/Makefile.am b/gst-libs/gst/player/Makefile.am
index 2f3a59a6a..46b194b07 100644
--- a/gst-libs/gst/player/Makefile.am
+++ b/gst-libs/gst/player/Makefile.am
@@ -12,6 +12,7 @@ libgstplayer_@GST_API_VERSION@_la_SOURCES = \
 libgstplayer_@GST_API_VERSION@_la_CFLAGS = \
 	-I$(top_srcdir)/gst-libs \
 	-I$(top_builddir)/gst-libs \
+	-DBUILDING_GST_PLAYER \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	$(GST_BASE_CFLAGS) \
 	$(GST_CFLAGS)
diff --git a/gst-libs/gst/player/meson.build b/gst-libs/gst/player/meson.build
index 3619de559..a615bcd96 100644
--- a/gst-libs/gst/player/meson.build
+++ b/gst-libs/gst/player/meson.build
@@ -25,7 +25,7 @@ install_headers(gstplayer_headers, subdir : 'gstreamer-' + api_version + '/gst/p
 
 gstplayer = library('gstplayer-' + api_version,
   gstplayer_sources,
-  c_args : gst_plugins_bad_args,
+  c_args : gst_plugins_bad_args + ['-DBUILDING_GST_PLAYER'],
   include_directories : [configinc, libsinc],
   version : libversion,
   soversion : soversion,
diff --git a/gst-libs/gst/player/player-prelude.h b/gst-libs/gst/player/player-prelude.h
index a24010a4b..2a8b87e66 100644
--- a/gst-libs/gst/player/player-prelude.h
+++ b/gst-libs/gst/player/player-prelude.h
@@ -25,7 +25,11 @@
 #include <gst/gst.h>
 
 #ifndef GST_PLAYER_API
-#define GST_PLAYER_API GST_EXPORT
+# ifdef BUILDING_GST_PLAYER
+#  define GST_PLAYER_API GST_API_EXPORT         /* from config.h */
+# else
+#  define GST_PLAYER_API GST_API_IMPORT
+# endif
 #endif
 
 #endif /* __GST_PLAYER_PRELUDE_H__ */
diff --git a/gst-libs/gst/sctp/Makefile.am b/gst-libs/gst/sctp/Makefile.am
index 56ef20867..4648e9c87 100644
--- a/gst-libs/gst/sctp/Makefile.am
+++ b/gst-libs/gst/sctp/Makefile.am
@@ -7,6 +7,7 @@ libgstsctp_1_0_la_SOURCES = \
 libgstsctp_1_0_la_CFLAGS = \
     -I$(top_srcdir)/gst-libs \
     -I$(top_builddir)/gst-libs \
+    -DBUILDING_GST_SCTP \
     $(GST_PLUGINS_BASE_CFLAGS) \
     $(GST_BASE_CFLAGS) \
     $(GST_CFLAGS)
diff --git a/gst-libs/gst/sctp/meson.build b/gst-libs/gst/sctp/meson.build
index b3d12a454..876f990e8 100644
--- a/gst-libs/gst/sctp/meson.build
+++ b/gst-libs/gst/sctp/meson.build
@@ -13,7 +13,7 @@ install_headers(sctp_headers, subdir : 'gstreamer-1.0/gst/sctp')
 
 libgstsctp = library('gstsctp-' + api_version,
   sctp_sources,
-  c_args : gst_plugins_bad_args,
+  c_args : gst_plugins_bad_args + ['-DBUILDING_GST_SCTP'],
   include_directories : [configinc, libsinc],
   version : libversion,
   soversion : soversion,
diff --git a/gst-libs/gst/sctp/sctp-prelude.h b/gst-libs/gst/sctp/sctp-prelude.h
index b89984c2f..ac16e9d7f 100644
--- a/gst-libs/gst/sctp/sctp-prelude.h
+++ b/gst-libs/gst/sctp/sctp-prelude.h
@@ -25,7 +25,11 @@
 #include <gst/gst.h>
 
 #ifndef GST_SCTP_API
-#define GST_SCTP_API GST_EXPORT
+# ifdef BUILDING_GST_SCTP
+#  define GST_SCTP_API GST_API_EXPORT         /* from config.h */
+# else
+#  define GST_SCTP_API GST_API_IMPORT
+# endif
 #endif
 
 #endif /* __GST_SCTP_PRELUDE_H__ */
diff --git a/gst-libs/gst/sctp/sctpreceivemeta.c b/gst-libs/gst/sctp/sctpreceivemeta.c
index 9fcff236f..e1c77d466 100644
--- a/gst-libs/gst/sctp/sctpreceivemeta.c
+++ b/gst-libs/gst/sctp/sctpreceivemeta.c
@@ -22,6 +22,9 @@
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  * OF SUCH DAMAGE.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include "sctpreceivemeta.h"
 
diff --git a/gst-libs/gst/sctp/sctpsendmeta.c b/gst-libs/gst/sctp/sctpsendmeta.c
index e2083af9b..d8ce14fc9 100644
--- a/gst-libs/gst/sctp/sctpsendmeta.c
+++ b/gst-libs/gst/sctp/sctpsendmeta.c
@@ -22,6 +22,9 @@
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  * OF SUCH DAMAGE.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include "sctpsendmeta.h"
 
diff --git a/gst-libs/gst/uridownloader/Makefile.am b/gst-libs/gst/uridownloader/Makefile.am
index d12257aed..7447e43bf 100644
--- a/gst-libs/gst/uridownloader/Makefile.am
+++ b/gst-libs/gst/uridownloader/Makefile.am
@@ -12,6 +12,7 @@ libgsturidownloader_@GST_API_VERSION@include_HEADERS = \
 libgsturidownloader_@GST_API_VERSION@_la_CFLAGS = \
 	$(GST_PLUGINS_BAD_CFLAGS) \
 	-DGST_USE_UNSTABLE_API \
+	-DBUILDING_GST_URI_DOWNLOADER \
 	$(GST_CFLAGS)
 
 libgsturidownloader_@GST_API_VERSION@_la_LIBADD = \
diff --git a/gst-libs/gst/uridownloader/gstfragment.c b/gst-libs/gst/uridownloader/gstfragment.c
index dd9c615ed..570375a4b 100644
--- a/gst-libs/gst/uridownloader/gstfragment.c
+++ b/gst-libs/gst/uridownloader/gstfragment.c
@@ -18,6 +18,9 @@
  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include <glib.h>
 #include <gst/base/gsttypefindhelper.h>
diff --git a/gst-libs/gst/uridownloader/gsturidownloader.c b/gst-libs/gst/uridownloader/gsturidownloader.c
index afc7c01dd..d33d85124 100644
--- a/gst-libs/gst/uridownloader/gsturidownloader.c
+++ b/gst-libs/gst/uridownloader/gsturidownloader.c
@@ -18,6 +18,9 @@
  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include <glib.h>
 #include "gstfragment.h"
diff --git a/gst-libs/gst/uridownloader/meson.build b/gst-libs/gst/uridownloader/meson.build
index cccb3b61e..7bea2fbcc 100644
--- a/gst-libs/gst/uridownloader/meson.build
+++ b/gst-libs/gst/uridownloader/meson.build
@@ -12,7 +12,7 @@ install_headers(urid_headers, subdir : 'gstreamer-1.0/gst/uridownloader')
 
 gsturidownloader = library('gsturidownloader-' + api_version,
   urid_sources,
-  c_args : gst_plugins_bad_args + [ '-DGST_USE_UNSTABLE_API' ],
+  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API', '-DBUILDING_GST_URI_DOWNLOADER'],
   include_directories : [configinc, libsinc],
   version : libversion,
   soversion : soversion,
diff --git a/gst-libs/gst/uridownloader/uridownloader-prelude.h b/gst-libs/gst/uridownloader/uridownloader-prelude.h
index f5ad5843c..92a6abbf6 100644
--- a/gst-libs/gst/uridownloader/uridownloader-prelude.h
+++ b/gst-libs/gst/uridownloader/uridownloader-prelude.h
@@ -25,7 +25,11 @@
 #include <gst/gst.h>
 
 #ifndef GST_URI_DOWNLOADER_API
-#define GST_URI_DOWNLOADER_API GST_EXPORT
+# ifdef BUILDING_GST_URI_DOWNLOADER
+#  define GST_URI_DOWNLOADER_API GST_API_EXPORT         /* from config.h */
+# else
+#  define GST_URI_DOWNLOADER_API GST_API_IMPORT
+# endif
 #endif
 
 #endif /* __GST_URI_DOWNLOADER_PRELUDE_H__ */
diff --git a/gst-libs/gst/video/Makefile.am b/gst-libs/gst/video/Makefile.am
index c8d2eb636..481d2654e 100644
--- a/gst-libs/gst/video/Makefile.am
+++ b/gst-libs/gst/video/Makefile.am
@@ -10,6 +10,7 @@ nodist_libgstbadvideo_@GST_API_VERSION@_la_SOURCES = $(BUILT_SOURCES)
 
 libgstbadvideo_@GST_API_VERSION@_la_CFLAGS = \
 	-DGST_USE_UNSTABLE_API \
+	-DBUILDING_GST_VIDEO_BAD \
 	-I$(top_srcdir)/gst-libs \
 	-I$(top_builddir)/gst-libs \
 	$(GST_CFLAGS) $(ORC_CFLAGS) \
diff --git a/gst-libs/gst/video/meson.build b/gst-libs/gst/video/meson.build
index a1432db25..58e1cd6fb 100644
--- a/gst-libs/gst/video/meson.build
+++ b/gst-libs/gst/video/meson.build
@@ -10,7 +10,7 @@ install_headers(badvideo_headers, subdir : 'gstreamer-1.0/gst/video')
 
 gstbadvideo = library('gstbadvideo-' + api_version,
   badvideo_sources,
-  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API'],
+  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API', '-DBUILDING_GST_VIDEO_BAD'],
   include_directories : [configinc, libsinc],
   version : libversion,
   soversion : soversion,
diff --git a/gst-libs/gst/video/video-bad-prelude.h b/gst-libs/gst/video/video-bad-prelude.h
index 3638a421f..8303b5022 100644
--- a/gst-libs/gst/video/video-bad-prelude.h
+++ b/gst-libs/gst/video/video-bad-prelude.h
@@ -25,7 +25,11 @@
 #include <gst/gst.h>
 
 #ifndef GST_VIDEO_BAD_API
-#define GST_VIDEO_BAD_API GST_EXPORT
+# ifdef BUILDING_GST_VIDEO_BAD
+#  define GST_VIDEO_BAD_API GST_API_EXPORT         /* from config.h */
+# else
+#  define GST_VIDEO_BAD_API GST_API_IMPORT
+# endif
 #endif
 
 #endif /* __GST_VIDEO_BAD_PRELUDE_H__ */
diff --git a/gst-libs/gst/wayland/Makefile.am b/gst-libs/gst/wayland/Makefile.am
index 743a48960..a9f3f7b57 100644
--- a/gst-libs/gst/wayland/Makefile.am
+++ b/gst-libs/gst/wayland/Makefile.am
@@ -9,6 +9,7 @@ libgstwayland_@GST_API_VERSION@_la_CFLAGS = \
 	$(GST_PLUGINS_BAD_CFLAGS) \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	$(GST_CFLAGS) \
+	-DBUILDING_GST_WAYLAND \
 	$(WAYLAND_CFLAGS)
 
 libgstwayland_@GST_API_VERSION@_la_LIBADD = \
diff --git a/gst-libs/gst/wayland/meson.build b/gst-libs/gst/wayland/meson.build
index ddade69cd..8bfefcb3b 100644
--- a/gst-libs/gst/wayland/meson.build
+++ b/gst-libs/gst/wayland/meson.build
@@ -9,7 +9,7 @@ use_wayland = wl_protocol_dep.found() and wl_client_dep.found() and wl_scanner.f
 if use_wayland
   gstwayland = library('gstwayland-' + api_version,
     'wayland.c',
-    c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API'],
+    c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API', '-DBUILDING_GST_WAYLAND'],
     include_directories : [configinc, libsinc],
     version : libversion,
     soversion : soversion,
diff --git a/gst-libs/gst/wayland/wayland.h b/gst-libs/gst/wayland/wayland.h
index 5cc0e5f74..c60c57ccd 100644
--- a/gst-libs/gst/wayland/wayland.h
+++ b/gst-libs/gst/wayland/wayland.h
@@ -30,7 +30,11 @@
 #include <wayland-client.h>
 
 #ifndef GST_WAYLAND_API
-#define GST_WAYLAND_API GST_EXPORT
+# ifdef BUILDING_GST_WAYLAND
+#  define GST_WAYLAND_API GST_API_EXPORT         /* from config.h */
+# else
+#  define GST_WAYLAND_API GST_API_IMPORT
+# endif
 #endif
 
 G_BEGIN_DECLS
diff --git a/gst-libs/gst/webrtc/Makefile.am b/gst-libs/gst/webrtc/Makefile.am
index 945c4c079..edc9de0aa 100644
--- a/gst-libs/gst/webrtc/Makefile.am
+++ b/gst-libs/gst/webrtc/Makefile.am
@@ -38,6 +38,7 @@ nodist_libgstwebrtc_@GST_API_VERSION@include_HEADERS = $(built_headers)
 libgstwebrtc_@GST_API_VERSION@_la_CFLAGS = \
 	-I$(top_builddir)/gst-libs \
 	-I$(top_srcdir)/gst-libs \
+	-DBUILDING_GST_WEBRTC \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	$(GST_BASE_CFLAGS) \
 	$(GST_CFLAGS) \
diff --git a/gst-libs/gst/webrtc/meson.build b/gst-libs/gst/webrtc/meson.build
index 24e43765e..a9f11dc59 100644
--- a/gst-libs/gst/webrtc/meson.build
+++ b/gst-libs/gst/webrtc/meson.build
@@ -27,6 +27,7 @@ webrtc_enumtypes_headers = [
 
 webrtc_enums = gnome.mkenums_simple('webrtc-enumtypes',
   sources : webrtc_enumtypes_headers,
+  body_prefix : '#ifdef HAVE_CONFIG_H\n#include "config.h"\n#endif',
   header_prefix : '#include <gst/webrtc/webrtc_fwd.h>',
   decorator: 'GST_WEBRTC_API',
   install_header: true,
@@ -41,7 +42,7 @@ gstwebrtc_dependencies = [gstbase_dep, gstsdp_dep]
 
 gstwebrtc = library('gstwebrtc-' + api_version,
   webrtc_sources, gstwebrtc_c, gstwebrtc_h,
-  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API'],
+  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API', '-DBUILDING_GST_WEBRTC'],
   include_directories : [configinc, libsinc],
   version : libversion,
   soversion : soversion,
diff --git a/gst-libs/gst/webrtc/webrtc_fwd.h b/gst-libs/gst/webrtc/webrtc_fwd.h
index 2e50125f5..e7309e36d 100644
--- a/gst-libs/gst/webrtc/webrtc_fwd.h
+++ b/gst-libs/gst/webrtc/webrtc_fwd.h
@@ -28,7 +28,11 @@
 #include <gst/gst.h>
 
 #ifndef GST_WEBRTC_API
-#define GST_WEBRTC_API GST_EXPORT
+# ifdef BUILDING_GST_WEBRTC
+#  define GST_WEBRTC_API GST_API_EXPORT         /* from config.h */
+# else
+#  define GST_WEBRTC_API GST_API_IMPORT
+# endif
 #endif
 
 #include <gst/webrtc/webrtc-enumtypes.h>
diff --git a/meson.build b/meson.build
index b52c0cd1c..b36a32d1b 100644
--- a/meson.build
+++ b/meson.build
@@ -32,6 +32,8 @@ plugins_install_dir = '@0@/gstreamer-1.0'.format(get_option('libdir'))
 cc = meson.get_compiler('c')
 cxx = meson.get_compiler('cpp')
 
+cdata = configuration_data()
+
 if cc.get_id() == 'msvc'
   # Ignore several spurious warnings for things gstreamer does very commonly
   # If a warning is completely useless and spammy, use '/wdXXXX' to suppress it
@@ -61,12 +63,17 @@ if cc.has_link_argument('-Wl,-Bsymbolic-functions')
 endif
 
 # Symbol visibility
-if cc.has_argument('-fvisibility=hidden')
+if cc.get_id() == 'msvc'
+  export_define = '__declspec(dllexport) extern'
+elif cc.has_argument('-fvisibility=hidden')
   add_project_arguments('-fvisibility=hidden', language: 'c')
+  export_define = 'extern __attribute__ ((visibility ("default")))'
+else
+  export_define = 'extern'
 endif
-if cxx.has_argument('-fvisibility=hidden')
-  add_project_arguments('-fvisibility=hidden', language: 'cpp')
-endif
+
+# Passing this through the command line would be too messy
+cdata.set('GST_API_EXPORT', export_define)
 
 # Disable strict aliasing
 if cc.has_argument('-fno-strict-aliasing')
@@ -100,7 +107,6 @@ if glib_checks.disabled() or (glib_checks.auto() and not gst_version_is_dev)
   add_project_arguments('-DG_DISABLE_CHECKS', language: 'c')
 endif
 
-cdata = configuration_data()
 check_headers = [
   ['HAVE_DLFCN_H', 'dlfcn.h'],
   ['HAVE_FCNTL_H', 'fcntl.h'],