Mention of gcc 4.5 as first version with plugin support

[Dave Johansen]

Currently, the plugin documentation doesn't mention that it requires
gcc 4.5 or later. The patch to add this statement is attached and
here's the ChangeLog:

2013-01-10  Dave Johansen  <davejohan...@gmail.com>

        * gcc/doc/plugins.texi: Added gcc.4.5.0 or later note to
Plugins documentation.

plugins_doc.patch
Description: Binary data