Composer install missing curl-ext
<p>I am developing some PHP on Ubuntu 14.04.4 LS. Running <code>composer install</code> is failing and I can't figure it out.  This was working earlier when I was using PHP 5.5.9, but I had to update to at least 5.6 in order to install phpunit.</p>

<p>Running <code>php -v</code> outputs:</p>

<pre><code>PHP 5.6.23-1+deb.sury.org~trusty+2 (cli) 
Copyright (c) 1997-2016 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2016 Zend Technologies
with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies
</code></pre>

<p>Running <code>which php</code> outputs:</p>

<pre><code>/usr/bin/php
</code></pre>

<p>which is kind of suspicious as it doesn't match <code>php -v</code> (/usr/bin has: "php", "php5", and "php5.6")</p>

<p>Here is my composer.json:</p>

<pre><code>{
    "require-dev": {
        "phpunit/phpunit": "5.4.*"
    },
    "require": {
        "silex/silex": "~1.3",
        "stripe/stripe-php": "3.*"
    }
}
</code></pre>

<p>Running <code>composer install</code> creates this output:</p>

<pre><code>$ composer install
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
- stripe/stripe-php v3.9.2 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.9.1 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.9.0 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.8.0 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.7.1 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.7.0 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.6.0 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.5.0 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.4.0 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.3.0 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.2.0 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.14.3 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.14.2 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.14.1 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.14.0 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.13.0 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.12.1 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.12.0 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.11.0 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.10.1 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.10.0 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.1.0 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.0.0 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- stripe/stripe-php v3.14.2 requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.
- Installation request for stripe/stripe-php 3.* -&gt; satisfiable by stripe/stripe-php[v3.0.0, v3.1.0, v3.10.0, v3.10.1, v3.11.0, v3.12.0, v3.12.1, v3.13.0, v3.14.0, v3.14.1, v3.14.2, v3.14.3, v3.2.0, v3.3.0, v3.4.0, v3.5.0, v3.6.0, v3.7.0, v3.7.1, v3.8.0, v3.9.0, v3.9.1, v3.9.2].

To enable extensions, verify that they are enabled in those .ini files:
- /etc/php/5.6/cli/php.ini
- /etc/php/5.6/cli/conf.d/10-opcache.ini
- /etc/php/5.6/cli/conf.d/10-pdo.ini
- /etc/php/5.6/cli/conf.d/20-calendar.ini
- /etc/php/5.6/cli/conf.d/20-ctype.ini
- /etc/php/5.6/cli/conf.d/20-exif.ini
- /etc/php/5.6/cli/conf.d/20-fileinfo.ini
- /etc/php/5.6/cli/conf.d/20-ftp.ini
- /etc/php/5.6/cli/conf.d/20-gettext.ini
- /etc/php/5.6/cli/conf.d/20-iconv.ini
- /etc/php/5.6/cli/conf.d/20-json.ini
- /etc/php/5.6/cli/conf.d/20-phar.ini
- /etc/php/5.6/cli/conf.d/20-posix.ini
- /etc/php/5.6/cli/conf.d/20-readline.ini
- /etc/php/5.6/cli/conf.d/20-shmop.ini
- /etc/php/5.6/cli/conf.d/20-sockets.ini
- /etc/php/5.6/cli/conf.d/20-sysvmsg.ini
- /etc/php/5.6/cli/conf.d/20-sysvsem.ini
- /etc/php/5.6/cli/conf.d/20-sysvshm.ini
- /etc/php/5.6/cli/conf.d/20-tokenizer.ini
You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.
</code></pre>

<p>I followed these instructions but it doesnt work: <a href="https://stackoverflow.com/questions/19335305/composer-install-error-requires-ext-curl-when-its-actualy-enabled">Composer install error - requires ext_curl when it&#39;s actually enabled</a></p>

<p>Running <code>php -i | grep php.ini</code> outputs:</p>

<pre><code>Configuration File (php.ini) Path =&gt; /etc/php/5.6/cli
Loaded Configuration File =&gt; /etc/php/5.6/cli/php.ini
</code></pre>

<p>Running: <code>sudo apt-get install php5-curl</code> outputs:</p>

<pre><code>php5-curl is already the newest version.
</code></pre>

<p>Running <code>curl -V</code> outputs:</p>

<pre><code>curl 7.35.0 (x86_64-pc-linux-gnu) libcurl/7.35.0 OpenSSL/1.0.1f zlib/1.2.8 libidn/1.28 librtmp/2.3
Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps pop3 pop3s rtmp rtsp smtp smtps telnet tftp 
Features: AsynchDNS GSS-Negotiate IDN IPv6 Largefile NTLM NTLM_WB SSL libz TLS-SRP 
</code></pre>

<p>Any help is appreciated.</p>