Make the git page more useful for current versions of PHP.

This is precipitated mostly by the fact that we no longer have snaps.php.net,
so this is likely to be more heavily trafficked than before.

This almost certainly requires more work, but at least this gets rid of the
most egregious problems.

git.php

@@ -44,12 +44,17 @@ site_header("Git Access", array("current" => "community"));
 </p>
 
 <ul>
- <li><i>autoconf</i>: 2.13 (2.59+ for PHP 5.4+)</li>
+ <li><i>autoconf</i>: 2.59+</li>
  <li><i>automake</i>: 1.4+</li>
  <li><i>libtool</i>: 1.4.x+ (except 1.4.2)</li>
- <li><i>bison</i>: 1.28, 1.35, 1.75, 2.0 or higher</li>
- <li><i>flex (PHP 5.2 and earlier)</i>: 2.5.4 (<strong>not higher</strong>)</li>
  <li><i>re2c</i>: 0.13.4+</li>
+ <li id="bison"><i>bison</i>:
+  <ul>
+   <li><i>PHP 5.4</i>: 1.28, 1.35, 1.75, 2.0 to 2.6.4</li>
+   <li><i>PHP 5.5 and 5.6</i>: 2.4 to 2.7</li>
+   <li><i>PHP 7</i>: 2.4+</li>
+  </ul>
+ </li>
 </ul>
 
 <p>
@@ -73,6 +78,13 @@ site_header("Git Access", array("current" => "community"));
   <br><br>
   <code>git clone http://git.php.net/repository/php-src.git</code>
   <br><br>
+
+  You can also download a snapshot from GitHub:<br><br>
+  <ul>
+   <li>Go to the <a href="https://github.com/php/php-src">php-src project page</a>.</li>
+   <li>Select the branch you're interested in from the branch dropdown.</li>
+   <li>Click on the <strong>Download ZIP</strong> button.</li>
+  </ul>
  </li>
 
  <li>
@@ -83,14 +95,17 @@ site_header("Git Access", array("current" => "community"));
  </li>
 
  <li>
-  You can then check out the branch you want to build:
+  You can then check out the branch you want to build, for example:
   <br><br>
-  <strong>PHP 5.3</strong>:
-  <code>git checkout PHP-5.3</code>
-  <br>
   <strong>PHP 5.4</strong>:
   <code>git checkout PHP-5.4</code>
   <br>
+  <strong>PHP 5.5</strong>:
+  <code>git checkout PHP-5.5</code>
+  <br>
+  <strong>PHP 5.6</strong>:
+  <code>git checkout PHP-5.6</code>
+  <br>
   <strong>PHP HEAD</strong>:
   <code>git checkout master</code>
   <br><br>
@@ -99,8 +114,8 @@ site_header("Git Access", array("current" => "community"));
  <li>
   <div class="tip" style="margin: 10px 0 10px 20px;">
    <p>Note that certain combinations of autoconf, automake and libtool may not
-   work when used together. See <a href="#buildconf_fail">below</a> for
-   details.<br>
+   work when used together, particularly with historical versions of PHP. See
+   <a href="#buildconf_fail">below</a> for details.<br>
    Also, certain versions of autoconf may generate warnings of <code>AC_PROG_CPP
    called before AC_PROG_CC</code>. These messages can usually be ignored.</p>
   </div>
@@ -112,10 +127,10 @@ site_header("Git Access", array("current" => "community"));
 
  <li>
   From this point onwards, installation is similar to the installation of one of
-  the official packages with one main difference &ndash; you may need bison 1.28 or later
-  and flex 2.5.4 (PHP 5.2 and earlier) or re2c 0.13.4+ or later (PHP 5.3 and later) to
-  compile, because the pre-generated scanner and parser files may not
-  be included in Git.
+  the official packages with one main difference &ndash; you will need
+  <a href="#bison">a version of bison that is supported for the PHP version you want to build</a>.
+  You may also require re2c if you intend to change any of the scanner and
+  parser files PHP uses.
  </li>
 </ol>
 
@@ -139,15 +154,16 @@ site_header("Git Access", array("current" => "community"));
 
 <p>
  The PHP manual is still currently hosted on SVN, although it will be migrated
- to Git in the near future. To checkout the latest English version of the PHP
+ to Git in the future. To checkout the latest English version of the PHP
  manual:<br>
  <code>svn checkout https://svn.php.net/repository/phpdoc/modules/doc-en ./phpdoc-en</code>
  <br><br>
  You can also check the <a href="https://wiki.php.net/vcs/svnfaq">SVN FAQ on the wiki</a>.
 </p>
 
-<a name="buildconf_fail"></a>
-<h2>autoconf, automake and libtool information</h2>
+<h2>Historical issues</h2>
+
+<h3 id="buildconf_fail">autoconf, automake and libtool information for PHP 5.3 and below</h3>
 
 <p>
  There seem to be problems with libtool 1.4.2. It is suggested
@@ -171,8 +187,7 @@ site_header("Git Access", array("current" => "community"));
  <code>PHP_AUTOCONF=autoconf213 PHP_AUTOHEADER=autoheader213 ./buildconf</code>
 </p>
 
-<a name="flex_fail"></a>
-<h2>Zend/zend_language_scanner.c: No such file or directory</h2>
+<h3 id="flex_fail">Zend/zend_language_scanner.c: No such file or directory</h3>
 
 <p>
  PHP only supports flex 2.5.4, <strong>not</strong> later versions as they broke backwards compatibility.