--- /dev/null
+#serial 1
+
+dnl From Paul Eggert.
+
+AC_DEFUN(AC_C_BACKSLASH_A,
+[
+ AC_CACHE_CHECK([whether backslash-a works in strings], ac_cv_c_backslash_a,
+ [AC_TRY_COMPILE([],
+ [
+ changequote(, ) dnl
+#if '\a' == 'a'
+ syntax error;
+#endif
+ char buf['\a' == 'a' ? -1 : 1];
+ buf[0] = '\a';
+ return buf[0] != "\a"[0];
+ changequote([, ])dnl
+ ],
+ ac_cv_c_backslash_a=yes,
+ ac_cv_c_backslash_a=no)])
+ if test $ac_cv_c_backslash_a = yes; then
+ AC_DEFINE(HAVE_C_BACKSLASH_A, 1,
+ [Define if backslash-a works in C strings.])
+ fi
+])