Insert notes about PHP 4.3.x into some documentation.

Added warning to src/login.php when PHP 4.3.x is in use.
Warning can be disabled by adding $shootMyFootOff = true; to config/config_local.php

ChangeLog

@@ -19,6 +19,8 @@ Version 1.4.0 CVS
     by register_globals = off.
   - Added Greek locale. Thanks to George P. Kremmydas 
     <george at kefalonia-ithaki.gr> and Alexandros Vellis <avel at noc.uoa.gr>
+  - Added notes about PHP 4.3.x to documentation, and a gaudy warning message
+    in src/login.php.  Warning can be disabled.
   
 Version 1.4.0 RC 2a
 -------------------

INSTALL

@@ -26,6 +26,10 @@ Table of Contents:
   latest release version of PHP4.
 
 a. Obtaining and compiling PHP4
+  
+  SquirrelMail has not been tested for use with PHP 4.3.x.  The
+  development team does not recommend the use of this software with
+  PHP 4.3.x until further testing can be done.
 
   Point your favorite webserver at http://www.php.net/version4/ and
   download the source. Untar (tar xvfz filename-you-downloaded.tgz)

ReleaseNotes

@@ -5,6 +5,7 @@
 
 In this edition of SquirrelMail Release Notes:
    * All about this Release!!!
+   * A note on PHP 4.3.x
    * Major updates
    * A note on plugins
    * Reporting my favorite SquirrelMail 1.4 bug
@@ -32,6 +33,21 @@ to verify that this is true!
 So download it! Install it, and try to break it! We are hungry for any
 bug report you send. Even the smallest issue deserves to be fixed.
 
+A note on PHP 4.3.x
+===================
+
+While the developers realize that PHP 4.3.x is the "latest and greatest"
+version of PHP to be available, SquirrelMail has not been extensively
+tested with it.  There may be potential session issues with PHP 4.3.x,
+and PHP by default has a session warning which will need to be disabled
+if you wish to use it with SquirrelMail.
+
+Put simply: The SquirrelMail team does not recommend the use of
+PHP 4.3.x with SquirrelMail at this time.
+
+SquirrelMail will put a large ugly warning about the use of PHP 4.3.x on
+the login screen unless you add "$shootMyFootOff = true;" to 
+config/config_local.php, or downgrade PHP.
 
 Major updates
 ==============

src/login.php

@@ -93,6 +93,18 @@ if (isset($org_logo) && $org_logo) {
         $width_and_height .= " height=\"$org_logo_height\"";
     }
 }
+global $shootMyFootOff;
+if (check_php_version(4,3) and !isset($shootMyFootOff)) {
+    echo '<center><hr width="75%">' . "\n";
+    echo '<h2>PHP 4.3.x has been detected</h2>' . "\n";
+    echo '</center><p>The SquirrelMail team does not recommend the use of PHP 4.3.x with';
+    echo ' this software.  Please see the <a href="http://www.squirrelmail.org">SquirrelMail';
+    echo ' website</a>, or the documentation that came with SquirrelMail for more information.</p>';
+    echo '<p>This warning can be disabled by either downgrading PHP, or inserting';
+    echo '"$shootMyFootOff = true;" in config/config_local.php.</p>' . "\n";
+    echo '<center><hr width="75%"></center>' . "\n";
+    echo "\n";
+}
 
 echo "\n" . '<form action="redirect.php" method="post">' . "\n" .
 html_tag( 'table',