安装到mcrypt的时候出现了问题
./configure
提示出错，首先提示
*** Could not run libmcrypt test program, checking why…
*** The test program failed to compile or link. See the file config.log for the
*** exact error that occured. This usually means LIBMCRYPT was incorrectly installed
*** or that you have moved LIBMCRYPT since it was installed. In the latter case, you
*** may want to edit the libmcrypt-config script: no
configure: error: *** libmcrypt was not found
找了相关资料，得出解决方法明明我安装了libmcrypt 2.5.8 ，可是竟然提示没有发现！然后在/usr/local/bin/找到了LIBMCRYPT_CONFIG ，这一步明确了是PATH变量的问题 ！
方法是ln -s /usr/local/bin/libmcrypt_config /usr/bin/libmcrypt_config
之后继续进行./configure
仍然报错：
*** Could not run libmcrypt test program, checking why…
*** The test program compiled, but did not run. This usually means
*** that the run-time linker is not finding LIBMCRYPT or finding the wrong
*** version of LIBMCRYPT. If it is not finding LIBMCRYPT, you'll need to set your
*** LD_LIBRARY_PATH environment variable, or edit /etc/ld.so.conf to point
*** to the installed location Also, make sure you have run ldconfig if that
*** is required on your system
***
*** If you have an old version installed, it is best to remove it, although
*** you may also be able to get things to work by modifying LD_LIBRARY_PATH
***
configure: error: *** libmcrypt was not found
继续查找，还是变量的问题
解决方法如下：运行 export LD_LIBRARY_PATH=/usr/local/lib: LD_LIBRARY_PATH
然后make ； make install
完成