dnl If ommitted, it defaults to `c_std'.
AC_DEFUN(GLIBCPP_ENABLE_CHEADERS, [dnl
define([GLIBCPP_ENABLE_CHEADERS_DEFAULT], ifelse($1, c_std, c_std, c_std))dnl
dnl If ommitted, it defaults to `c_std'.
AC_DEFUN(GLIBCPP_ENABLE_CHEADERS, [dnl
define([GLIBCPP_ENABLE_CHEADERS_DEFAULT], ifelse($1, c_std, c_std, c_std))dnl