--- a/modules/gettext
+++ b/modules/gettext
@@ -39,6 +39,15 @@
 AM_GNU_GETTEXT_VERSION([0.14.5])
 
 Makefile.am:
+# This is for those projects which use "gettextize --intl" to put a source-code
+# copy of libintl into their package. In such projects, every Makefile.am needs
+# -I$(top_builddir)/intl, so that <libintl.h> can be found in this directory.
+# For the Makefile.ams in other directories it is the maintainer's
+# responsibility; for the one from gnulib we do it here.
+# This option has no effect when the user disables NLS (because then the intl
+# directory contains no libintl.h file) or when the project does not use
+# "gettextize --intl".
+AM_CPPFLAGS += -I$(top_builddir)/intl
 
 Include:
 "gettext.h"