我需要安装 Tesseract，需要安装 autoconf automake libtool，但是我收到如下错误：
sahu@sahu-desktop:/$ sudo apt-get install autoconf
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package autoconf is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'autoconf' has no installation candidate
所以请帮助我。