+AC_CACHE_CHECK(whether preprocessor supports -Wunused-macros,
+ nmh_cv_has_unusedmacros,
+ [nmh_saved_cppflags="$CPPFLAGS"
+ CPPFLAGS="$CPPFLAGS -Wunused-macros -Wno-unused-macros"
+ AC_TRY_COMPILE([],[],nmh_cv_has_unusedmacros=yes,nmh_cv_has_unusedmacros=no)
+ CPPFLAGS="$nmh_saved_cppflags"])
+
+if test "$nmh_cv_has_unusedmacros" = 'yes'; then
+ test -z "$CPPLAGS" && CPPFLAGS=-Wunused-macros \
+ || CPPFLAGS="$CPPFLAGS -Wunused-macros"
+ DISABLE_UNUSED_MACROS_WARNING=-Wno-unused-macros
+fi
+AC_SUBST(DISABLE_UNUSED_MACROS_WARNING)dnl
+