Preventing installation of specific files

[mdoko]

Is it possible to instruct portage not to install specific files while merging a package?

Concrete problem I have is this: mail-client/thunderbird-17.0.2 installs th following files under /usr/lib64/thunderbird/searchplugins:

• amazondotcom.xml
  
• aol-web-search.xml
  
• bing.xml
  
• eBay.xml
  
• twitter.xml
  
• wikipedia.xml
  
• yahoo.xml

Since I'm not interested inusing any of those search engines from within my mail client, I would like not to have those files installed.

Is there any way to achieve this short of modifying the ebuild script?
_________________
A lie is a lie
even if everyone believes it.
The truth is the truth
even if no one believes it.

[Hu]

You could use INSTALL_MASK or PKG_INSTALL_MASK to instruct Portage not to install or package them. You could use a package-specific Portage environment file to define a post_src_install that removes those files, before the packaging and merge phases run.