Properly ignore symbol export macros for Doxygen.

src/MagnumPlugins/AnyAudioImporter/AnyImporter.h

@@ -45,6 +45,9 @@
     #define MAGNUM_ANYAUDIOIMPORTER_EXPORT CORRADE_VISIBILITY_STATIC
 #endif
 #define MAGNUM_ANYAUDIOIMPORTER_LOCAL CORRADE_VISIBILITY_LOCAL
+#else
+#define MAGNUM_ANYAUDIOIMPORTER_EXPORT
+#define MAGNUM_ANYAUDIOIMPORTER_LOCAL
 #endif
 
 namespace Magnum { namespace Audio {

src/MagnumPlugins/AnyImageConverter/AnyImageConverter.h

@@ -44,6 +44,9 @@
     #define MAGNUM_ANYIMAGECONVERTER_EXPORT CORRADE_VISIBILITY_STATIC
 #endif
 #define MAGNUM_ANYIMAGECONVERTER_LOCAL CORRADE_VISIBILITY_LOCAL
+#else
+#define MAGNUM_ANYIMAGECONVERTER_EXPORT
+#define MAGNUM_ANYIMAGECONVERTER_LOCAL
 #endif
 
 namespace Magnum { namespace Trade {

src/MagnumPlugins/AnyImageImporter/AnyImageImporter.h

@@ -44,6 +44,9 @@
     #define MAGNUM_ANYIMAGEIMPORTER_EXPORT CORRADE_VISIBILITY_STATIC
 #endif
 #define MAGNUM_ANYIMAGEIMPORTER_LOCAL CORRADE_VISIBILITY_LOCAL
+#else
+#define MAGNUM_ANYIMAGEIMPORTER_EXPORT
+#define MAGNUM_ANYIMAGEIMPORTER_LOCAL
 #endif
 
 namespace Magnum { namespace Trade {

src/MagnumPlugins/AnySceneImporter/AnySceneImporter.h

@@ -44,6 +44,9 @@
     #define MAGNUM_ANYSCENEIMPORTER_EXPORT CORRADE_VISIBILITY_STATIC
 #endif
 #define MAGNUM_ANYSCENEIMPORTER_LOCAL CORRADE_VISIBILITY_LOCAL
+#else
+#define MAGNUM_ANYSCENEIMPORTER_EXPORT
+#define MAGNUM_ANYSCENEIMPORTER_LOCAL
 #endif
 
 namespace Magnum { namespace Trade {