diff --git a/gst-libs/gst/gl/gstgldebug.c b/gst-libs/gst/gl/gstgldebug.c
index e0e8da7e15..2d8bbca6b2 100644
--- a/gst-libs/gst/gl/gstgldebug.c
+++ b/gst-libs/gst/gl/gstgldebug.c
@@ -239,8 +239,9 @@ _debug_type_to_string (GLenum type)
 }
 
 /* silence the compiler... */
-void GSTGLAPI _gst_gl_debug_callback (GLenum source, GLenum type, GLuint id,
-    GLenum severity, GLsizei length, const gchar * message, gpointer user_data);
+G_GNUC_INTERNAL void GSTGLAPI _gst_gl_debug_callback (GLenum source,
+    GLenum type, GLuint id, GLenum severity, GLsizei length,
+    const gchar * message, gpointer user_data);
 
 void GSTGLAPI
 _gst_gl_debug_callback (GLenum source, GLenum type, GLuint id, GLenum severity,
diff --git a/gst-libs/gst/gl/gstglfeature.h b/gst-libs/gst/gl/gstglfeature.h
index 0bbcda6c43..fdc3137abe 100644
--- a/gst-libs/gst/gl/gstglfeature.h
+++ b/gst-libs/gst/gl/gstglfeature.h
@@ -97,7 +97,7 @@ struct _GstGLFeatureData
 gboolean
 gst_gl_check_extension (const char *name, const gchar * ext);
 
-gboolean
+G_GNUC_INTERNAL gboolean
 _gst_gl_feature_check (GstGLContext *context,
                      const char *driver_prefix,
                      const GstGLFeatureData *data,
@@ -105,7 +105,7 @@ _gst_gl_feature_check (GstGLContext *context,
                      int gl_minor,
                      const char *extensions_string);
 
-void
+G_GNUC_INTERNAL void
 _gst_gl_feature_check_ext_functions (GstGLContext *context,
                                    int gl_major,
                                    int gl_minor,
diff --git a/gst-libs/gst/gl/gstglsl_private.h b/gst-libs/gst/gl/gstglsl_private.h
index c23ff911bb..c1be677ae4 100644
--- a/gst-libs/gst/gl/gstglsl_private.h
+++ b/gst-libs/gst/gl/gstglsl_private.h
@@ -55,8 +55,8 @@ typedef struct _GstGLSLFuncs
       GLsizei * length, char *log);
 } GstGLSLFuncs;
 
-gboolean _gst_glsl_funcs_fill (GstGLSLFuncs * vtable, GstGLContext * context);
-const gchar * _gst_glsl_shader_string_find_version (const gchar * str);
+G_GNUC_INTERNAL gboolean _gst_glsl_funcs_fill (GstGLSLFuncs * vtable, GstGLContext * context);
+G_GNUC_INTERNAL const gchar * _gst_glsl_shader_string_find_version (const gchar * str);
 
 G_END_DECLS
 
diff --git a/gst-libs/gst/gl/wayland/wayland_event_source.h b/gst-libs/gst/gl/wayland/wayland_event_source.h
index 940a5e0168..fa20892bee 100644
--- a/gst-libs/gst/gl/wayland/wayland_event_source.h
+++ b/gst-libs/gst/gl/wayland/wayland_event_source.h
@@ -36,7 +36,7 @@
 GSource * wayland_event_source_new (struct wl_display *display,
                                     struct wl_event_queue *queue);
 
-gint      gst_gl_wl_display_roundtrip_queue (struct wl_display *display,
+G_GNUC_INTERNAL gint      gst_gl_wl_display_roundtrip_queue (struct wl_display *display,
                                              struct wl_event_queue *queue);
 
 #endif /* __WAYLAND_EVENT_SOURCE_H__ */