How can I produce a Crystal executable with no dependencies?
<p>I'm writing a program in <a href="http://crystal-lang.org" rel="noreferrer">Crystal</a>, that I intend to compile and move to other systems for execution. Ideally, it should have no dependencies, as the target systems will be fresh installations of linux.</p>

<p>Sadly, I can't get around the libc dependency, so I will presumably have to compile the executable on a system possessing the lowest version of libc I wish to target. I figure it should be forward-compatible.</p>

<p>I'm having difficulty with libssl, however. Default installations of Debian Wheezy don't seem to come with libssl, so I get this error when running my executable:</p>

<pre><code>error while loading shared libraries: libssl.so.1.0.0:
cannot open shared object file: No such file or directory
</code></pre>

<p>I assume this dependency exists because I <code>require "http/client"</code> in my source. However, I make no ssl-related calls, as I only use it to connect to unsecured websites.</p>

<p>I apparently also have a dependency on <code>libevent-2.0.so.5</code>. Presumably all Crystal programs do. Who knows how many other dependencies Crystal has?</p>

<p>My executables have to run on a freshly-installed linux system. So, how can I produce a Crystal executable with no dependencies? Other than libc, I suppose.</p>