+# Extra prerequisites of lib/vasnprintf.c for supporting the 'a' directive.
+AC_DEFUN([gl_PREREQ_VASNPRINTF_DIRECTIVE_A],
+[
+ AC_REQUIRE([gl_PRINTF_DIRECTIVE_A])
+ case "$gl_cv_func_printf_directive_a" in
+ *yes)
+ ;;
+ *)
+ AC_DEFINE([NEED_PRINTF_DIRECTIVE_A], 1,
+ [Define if the vasnprintf implementation needs special code for
+ the 'a' and 'A' directives.])
+ AC_CHECK_FUNCS([nl_langinfo])
+ ;;
+ esac
+])
+