New section on external toolchain usage

      same buildroot source tree</a></li>

      <li><a href="#using_toolchain">Using the uClibc toolchain

      outside Buildroot</a></li>

      <li><a href="#external_toolchain">Use an external toolchain</a></li>

      <li><a href="#downloaded_packages">Location of downloaded packages</a>

      </li>

      <li><a href="#add_software">Extending Buildroot with more

export BUILDROOT_DL_DIR <shared download location>

</pre>

    <h2><a name="external_toolchain" id="external_toolchain"></a>Using

    an external toolchain</h2>

<p>It might be useful not to use the toolchain generated by

Buildroot, for example if you already have a toolchain that is known

to work for your specific CPU, or if the toolchain generation feature

of Buildroot is not sufficiently flexible for you (for example if you

need to generate a system with <i>glibc</i> instead of

<i>uClibc</i>). Buildroot supports using an <i>external

toolchain</i>.</p>

<p>To enable the use of an external toolchain, go in the

<code>Toolchain</code> menu, and&nbsp;:</p>

<ul>

  <li>Select the <code>External binary toolchain</code> toolchain

  type</li>

  <li>Adjust the <code>External toolchain path</code>

  appropriately. It should be set to a path where a bin/ directory

  contains your cross-compiling tools</li>

  <li>Adjust the <code>External toolchain prefix</code>, so that the

  prefix, suffixed with <code>-gcc</code> or <code>-ld</code> will

  correspond to your cross-compiling tools</li>

</ul>

<p>If you are using an external toolchain based on <i>uClibc</i>, the

<code>Core C library from the external toolchain</code> and

<code>Libraries to copy from the external toolchain</code> options

should already have correct values. However, if your external

toolchain is based on <i>glibc</i>, you'll have to change these values

according to your cross-compiling toolchain.</p>

<p>To generate external toolchains, we recommend using <a

href="http://ymorin.is-a-geek.org/dokuwiki/projects/crosstool">Crosstool-NG</a>.

It allows to generate toolchains based on <i>uClibc</i>, <i>glibc</i>

and <i>eglibc</i> for a wide range of architectures, and has good

community support.</p>

    <h2><a name="add_software" id="add_software"></a>Extending Buildroot with

    more software</h2>