--- glibmm-2.66.1/glib/glibmm/ustring.h.orig	2021-05-30 14:58:12.510847400 -0700
+++ glibmm-2.66.1/glib/glibmm/ustring.h	2021-05-30 14:58:43.260848700 -0700
@@ -1076,8 +1076,8 @@
 {
 public:
   // noncopyable
-  GLIBMM_API FormatStream(const ustring::FormatStream&) = delete;
-  GLIBMM_API FormatStream& operator=(const ustring::FormatStream&) = delete;
+  FormatStream(const ustring::FormatStream&) = delete;
+  FormatStream& operator=(const ustring::FormatStream&) = delete;
 
 private:
 #ifdef GLIBMM_HAVE_WIDE_STREAM
