Improve MacOS support

Change-Id: Id54a73c025d01ee37d2373a62506eb52a4f75d35
diff --git a/src/export.h b/src/export.h
new file mode 100644
index 0000000..b4ff5d2
--- /dev/null
+++ b/src/export.h
@@ -0,0 +1,16 @@
+// export.h
+
+#ifndef EXPORT_H
+#define EXPORT_H
+
+#ifdef _WIN32
+    #ifdef BUILDING_DLL
+        #define DLL_EXPORT __declspec(dllexport)
+    #else
+        #define DLL_EXPORT __declspec(dllimport)
+    #endif
+#else
+    #define DLL_EXPORT __attribute__((visibility("default")))
+#endif
+
+#endif // EXPORT_H