diff --git a/gtk/gtkwin32theme.c b/gtk/gtkwin32theme.c
index 161df961c2..6fb480e223 100644
--- a/gtk/gtkwin32theme.c
+++ b/gtk/gtkwin32theme.c
@@ -200,8 +200,8 @@ _gtk_win32_theme_part_create_surface (HTHEME theme,
   cairo_t *cr;
   int x_offs;
   int y_offs;
-  gboolean has_alpha;
 #ifdef G_OS_WIN32
+  gboolean has_alpha;
   HDC hdc;
   RECT rect;
   SIZE size;