--- a/modules/locale
+++ b/modules/locale
@@ -7,6 +7,7 @@
 
 Depends-on:
 arg-nonnull
+c++defs
 extensions
 include_next
 stddef
@@ -20,15 +21,17 @@
 
 # We need the following in order to create <locale.h> when the system
 # doesn't have one that provides all definitions.
-locale.h: locale.in.h $(WARN_ON_USE_H) $(ARG_NONNULL_H)
+locale.h: locale.in.h $(CXXDEFS_H) $(ARG_NONNULL_H) $(WARN_ON_USE_H)
 	$(AM_V_GEN)rm -f $@-t $@ && \
 	{ echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */' && \
 	  sed -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
 	      -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
 	      -e 's|@''NEXT_LOCALE_H''@|$(NEXT_LOCALE_H)|g' \
 	      -e 's|@''GNULIB_DUPLOCALE''@|$(GNULIB_DUPLOCALE)|g' \
+	      -e 's|@''HAVE_DUPLOCALE''@|$(HAVE_DUPLOCALE)|g' \
 	      -e 's|@''HAVE_XLOCALE_H''@|$(HAVE_XLOCALE_H)|g' \
 	      -e 's|@''REPLACE_DUPLOCALE''@|$(REPLACE_DUPLOCALE)|g' \
+	      -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \
 	      -e '/definition of _GL_ARG_NONNULL/r $(ARG_NONNULL_H)' \
 	      -e '/definition of _GL_WARN_ON_USE/r $(WARN_ON_USE_H)' \
 	      < $(srcdir)/locale.in.h; \