--- courier-unicode.h.in.orig	2017-03-09 13:51:25.000000000 +0000
+++ courier-unicode.h.in	2017-11-30 10:38:17.000000000 +0000
@@ -55,6 +55,9 @@
 extern const char *unicode_locale_chset();
 
 #if @LANGINFO_L@
+#include <langinfo.h>
+#include <xlocale.h>
+
 extern const char *unicode_locale_chset_l(locale_t l);
 #endif