diff --git a/include/winnt.h b/include/winnt.h
index 2309ae32d67..559a7198ba4 100644
--- a/include/winnt.h
+++ b/include/winnt.h
@@ -148,13 +148,13 @@ extern "C" {
 # define DECLSPEC_EXPORT __declspec(dllexport)
 #elif defined(__MINGW32__)
 # define DECLSPEC_EXPORT __attribute__((dllexport))
-#elif defined(__GNUC__) && ((__GNUC__ > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 3)))
+#elif defined(__GNUC__) && ((__GNUC__ > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 3))) && !defined(__sun)
 # define DECLSPEC_EXPORT __attribute__((visibility ("default")))
 #else
 # define DECLSPEC_EXPORT
 #endif
 
-#if defined(_MSC_VER) || defined(__MINGW32__) || defined(__CYGWIN__)
+#if defined(_MSC_VER) || defined(__MINGW32__) || defined(__CYGWIN__) || defined(__sun)
 # define DECLSPEC_HIDDEN
 #elif defined(__GNUC__) && ((__GNUC__ > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 3)))
 # define DECLSPEC_HIDDEN __attribute__((visibility ("hidden")))