64位编译

       1）configure过程失败如下，

        checking run-time libs availability... failed

        configure: error: one or more libs available at link-time are not available run-time. Libs used at link-time: -lidn -lssh2 -lssl -lcrypto -lssl -lcrypto -ldl -lz -lldap -lz -lrt

        找了一下，这些库都分别在/usr/lib64和/usr/local/lib目录下（libssh2.so在/usr/local/lib目录下，其他的在/usr/lib64），

       export LD_LIBRARY_PATH=/usr/local/lib:/usr/lib64:$LD_LIBRARY_PATH 

       再次configure，成功!显示各个模块的支持情况如下

curl version: 7.37.1  
Host setup: x86_64-unknown-linux-gnu  
Install prefix: /usr/local  
Compiler: gcc  
SSL support: enabled (OpenSSL)  
SSH support: enabled (libSSH2)  
zlib support: enabled
...

编译支持SFTP的libcurl

./configure --with-ssl --with-libssh2