安装PHP时，在第一步编译配置的时候出现以下信息。一时不得其解，最后看了一下信息内容，有一个错误日志文件debug.log。在错误日志文件里提到了error while loading shared libraries: libltdl.so.3: cannot open shared object file: No such file or director。就是系统缺少libltdl3的意思。
于是在网上下载了https://rpmfind.net/linux/rpm2html/search.php?query=libltdl3&submit=Search+...&system=&arch=
libltdl3-1.5.18-1mdk.i586.rpm 安装成功后。重新编译安装PHP，成功。
提示：
1、libltdl.so.3 出现so的一般表示模块，而不是表示某个安装包。但可以根据模块的名称大致知道是什么软件包。
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| *** ATTENTION *** |
| |
| Something is likely to be messed up here, because the configure |
| script was not able to detect a simple feature on your platform. |
| This is often caused by incorrect configuration parameters. Please |
| see the file debug.log for error messages. |
| |
| If you are unable to fix this, send the file debug.log to the |
| [email protected] mailing list and include appropiate |
| information about your setup. |
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| License: |
| This software is subject to the PHP License, available in this |
| distribution in the file LICENSE. By continuing this installation |
| process, you are bound by the terms of this license agreement. |
| If you do not agree with the terms of this license, you must abort |
| the installation process at this point. |
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