title: curl error with brew install php56 --with-cgi
body: <p>After running the following commands, I get a curl error on OSX Yosemite. I can use brew in others but not for php56. I can download from <code>https://www.php.net/get/php-5.6.10.tar.bz2/from/this/mirror</code> but not through curl. How can I fix the problem?</p>
  
  <pre><code>brew tap homebrew/dupes
  brew tap homebrew/versions
  brew tap homebrew/homebrew-php
  brew options php56
  brew install --with-cgi php56
  
  ==&gt; Installing php56 from homebrew/homebrew-php
  ==&gt; Downloading https://www.php.net/get/php-5.6.10.tar.bz2/from/this/mirror
  
  curl: (60) SSL certificate problem: Invalid certificate chain
  More details here: http://curl.haxx.se/docs/sslcerts.html
  
  curl performs SSL certificate verification by default, using a "bundle"
   of Certificate Authority (CA) public keys (CA certs). If the default
   bundle file isn't adequate, you can specify an alternate file
   using the --cacert option.
  If this HTTPS server uses a certificate signed by a CA represented in
   the bundle, the certificate verification probably failed due to a
   problem with the certificate (it might be expired, or the name might
   not match the domain name in the URL).
  If you'd like to turn off curl's verification of the certificate, use
   the -k (or --insecure) option.
  Error: Failed to download resource "php56"
  Download failed: https://www.php.net/get/php-5.6.10.tar.bz2/from/this/mirror
  </code></pre>