This plug-in is fixed for running on the latest version of Squirrel and Eclipse.
The text below is copied from feature.xml of the original SQDEV plug-in.

<?xml version="1.0" encoding="UTF-8"?>
<feature
      id="org.squirrel_lang.sqdev.feature"
      label="Squirrel Development Tools"
      version="1.1.1"
      provider-name="SQDev Team"
      nl="en_US">

   <description url="http://sqdev.sf.net">
      Squirrel development tools, including syntax highlighting, outline
view, and debugging support.
   </description>

   <copyright url="http://www.squirrel-lang.org">
      SQDev is copyright 2006 Alberto Demichelis (with other contributors).
   </copyright>

   <license url="http://www.zlib.net/zlib_license.html">
      This software is provided &apos;as-is&apos;, without any express or implied
warranty.  In no event will the authors be held liable for any
damages arising from the use of this software.
-
Permission is granted to anyone to use this software for any
purpose, including commercial applications, and to alter it and
redistribute it freely, subject to the following restrictions:
-
1. The origin of this software must not be misrepresented; you
must not claim that you wrote the original software. If you use
this software in a product, an acknowledgment in the product
documentation would be appreciated but is not required.
-
2. Altered source versions must be plainly marked as such, and
must not be misrepresented as being the original software.
-
3. This notice may not be removed or altered from any source
distribution.
   </license>

   <plugin
         id="org.squirrel_lang.sqdev"
         download-size="0"
         install-size="0"
         version="1.1.1"/>

   <plugin
         id="org.squirrel_lang.sqdev.debug"
         download-size="0"
         install-size="0"
         version="1.1.1"/>

</feature>