redhat9.0安装rtorrent的问题，请高手赐教！

[kings6681988]

已经根据网上教程安装了curl-7.17.1 libsigc++-2.0.18 libtorrent-0.11.5，在安装最后一个stb-rtorrent的时候make出现错误：
manager.cc: In member function `void player::Manager::construct_player()':
manager.cc:76: `sleep' undeclared (first use this function)
manager.cc:76: (Each undeclared identifier is reported only once for each
function it appears in.)
manager.cc:85: `usleep' undeclared (first use this function)
make[3]: *** [manager.o] Error 1
make[3]: Leaving directory `/home/rtorrent/stb-rtorrent/src/player'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/home/rtorrent/stb-rtorrent/src'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/rtorrent/stb-rtorrent'
make: *** [all] Error 2

这是什么原因呢？重新装了好多次都是这个错误，请教！

[kings6681988]

没人回答么？

[kings6681988]

up!