When compiling a software package that is dependent on OpenSSL, it might happen that your compiler will give you the following error:
configure: error: Cannot find OpenSSL’s <evp.h> or <hmac.h>
in this case, the compiler wants to tell you that you haven’t the openSSL developer library installed. Do so by:
sudo apt-get install openssl-dev
on some systems, like Ubuntu Feisty, you might need to use this command:
sudo apt-get install libcurl3-openssl-dev