dnl ----------------------------------------------------------------------dnl This whole bit snagged from libstdc++-v3.dnldnl GCC_ENABLEdnl (FEATURE, DEFAULT, HELP-ARG, HELP-STRING)dnl (FEATURE, DEFAULT, HELP-ARG, HELP-STRING, permit a|b|c)dnl (FEATURE, DEFAULT, HELP-ARG, HELP-STRING, SHELL-CODE-HANDLER)dnldnl See docs/html/17_intro/configury.html#enable for documentation.dnlAC_DEFUN([GCC_ENABLE],[dnlm4_define([_g_switch],[--enable-$1])dnlm4_define([_g_help],[AC_HELP_STRING(_g_switch$3,[$4 @<:@default=$2@:>@])])dnlAC_ARG_ENABLE($1,_g_help,m4_bmatch([$5],[^permit ],[[case "$enableval" inm4_bpatsubst([$5],[permit ])) ;;*) AC_MSG_ERROR(Unknown argument to enable/disable $1) ;;dnl Idea for future: generate a URL pointing todnl "onlinedocs/configopts.html#whatever"esac]],[^$],[[case "$enableval" inyes|no) ;;*) AC_MSG_ERROR(Argument to enable/disable $1 must be yes or no) ;;esac]],[[$5]]),[enable_]m4_bpatsubst([$1],-,_)[=][$2])m4_undefine([_g_switch])dnlm4_undefine([_g_help])dnl])