--------------------------------------------

Checking for required software...

 * GNU C++ compiler... found at /usr/bin/g++
 * The 'make' tool... found at /usr/bin/make
 * A download tool like 'wget' or 'curl'... found at /usr/bin/wget
 * Ruby development headers... found
 * OpenSSL support for Ruby... found
 * RubyGems... found
 * Rake... found at /home/mygdp/.rvm/wrappers/ruby-xxx/rake
 * rack... found
 * Curl development headers with SSL support... not found
 * OpenSSL development headers... found
 * Zlib development headers... found

Some required software is not installed.
But don't worry, this installer will tell you how to install them.

Press Enter to continue, or Ctrl-C to abort.

--------------------------------------------

sudo apt-get install libcurl4-openssl-dev

转：http://www.ur-ban.com/blog/2010/11/26/curl-development-headers-with-ssl-support/