+AC_MSG_CHECKING(how to send mail)
+AC_ARG_WITH(mail,
+[ --with-mail=name How to send mail; one of:
+ sendmail (the default), smtp],
+[],
+[withval="sendmail"])
+if test -r "${srcdir}/src/mail-${withval}.c" ; then
+ AC_MSG_RESULT([$withval])
+ MODULE_OBJS="$MODULE_OBJS mail-${withval}.\$(OBJEXT)"
+else
+ AC_MSG_ERROR([Unknown mail method $withval])
+fi
+
+AC_MSG_CHECKING([I/O multiplexing backends])
+IOMUXES=""
+
+if test "x$ac_cv_func_select" = xyes ; then
+ AC_DEFINE(WITH_IOSET_SELECT, 1, [Define if using the select() I/O backend])
+ MODULE_OBJS="$MODULE_OBJS ioset-select.\$(OBJEXT)"
+ IOMUXES="$IOMUXES select"
+fi
+
+AC_ARG_WITH([epoll],
+[ --without-epoll Disables the epoll_*() I/O backend],
+[],
+[withval="$ac_cv_func_epoll_create"])
+if test "x$withval" = xyes ; then
+ AC_DEFINE(WITH_IOSET_EPOLL, 1, [Define if using the epoll I/O backend])
+ MODULE_OBJS="$MODULE_OBJS ioset-epoll.\$(OBJEXT)"
+ IOMUXES="$IOMUXES epoll"
+fi
+
+AC_ARG_WITH([kevent],
+[ --without-kevent Disables the kevent() I/O backend],
+[],
+[withval="$ac_cv_func_kevent"])
+if test "x$withval" = xyes ; then
+ AC_DEFINE(WITH_IOSET_KEVENT, 1, [Define if using the kevent I/O backend])
+ MODULE_OBJS="$MODULE_OBJS ioset-kevent.\$(OBJEXT)"
+ IOMUXES="$IOMUXES kevent"
+fi
+
+AC_ARG_WITH([win32],
+[ --with-win32 Enables the Win32 I/O backend],
+[],
+[withval="no"])
+if test "x$withval" = xyes ; then
+ AC_DEFINE(WITH_IOSET_WIN32, 1, [Define if using the Win32 I/O backend])
+ MODULE_OBJS="$MODULE_OBJS ioset-win32.\$(OBJEXT)"
+ IOMUXES="$IOMUXES win32"
+fi
+
+IOMUXES=`echo $IOMUXES | sed 's/^ +//'`
+if test "x$IOMUXES" = "x" ; then
+ AC_MSG_ERROR([No supported I/O multiplexing backend found])
+else
+ AC_MSG_RESULT($IOMUXES)
+fi
+