title: Installing php@7.3 in a new macbook pro with the new A1 chip(apple silicon)
body: <p>I am trying to install HD-Wallet Derive on my new Macbook Pro with the Apple A1 chip.
  For which I need to install install the latest version of PHP (7.3 at this current time)
  So when I hit this command <code>brew install php@7.3</code> on my terminal(zsh) and I get this Error message: <code>Error: php@7.3: no bottle available!</code></p>
  <p>You can try to install from source with:
  brew install --build-from-source php@7.3
  Please note building from source is unsupported. You will encounter build
  failures with some formulae. If you experience any issues please create pull
  requests instead of asking for help on Homebrew's GitHub, Twitter or any other
  official channels.</p>
  <p>I am building it from source. Using this repo. <a href="https://github.com/dan-da/hd-wallet-derive#installation-and-running" rel="nofollow noreferrer">https://github.com/dan-da/hd-wallet-derive#installation-and-running</a>  I was able to execute this commands <code>curl https://getcomposer.org/installer -o installer.php</code> and this <code>php installer.php</code> successfully. But when I ran this one <code>php composer.phar install</code></p>
  <p>I get this error:
  No lock file found. Updating dependencies instead of installing from lock file. Use composer update over composer install if you do not have a lock file.</p>
  <p>Loading composer repositories with package information
  Updating dependencies
  Your requirements could not be resolved to an installable set of packages.</p>
  <p>Problem 1
  - mdanter/ecc[v0.5.0, ..., 0.5.x-dev] require ext-gmp * -&gt; it is missing from your system. Install or enable PHP's gmp extension.
  - bitwasp/bitcoin dev-master requires mdanter/ecc ^0.5.0 -&gt; satisfiable by mdanter/ecc[v0.5.0, v0.5.1, v0.5.2, 0.5.x-dev].
  - Root composer.json requires bitwasp/bitcoin dev-master#8782bc6c470e342d4e0cb67eb036974f133b950b -&gt; satisfiable by bitwasp/bitcoin[dev-master].</p>
  <p>I believe I have to do a gmp extension but not sure how.</p>
  <p>Any advice is appreciated!</p>