linux: pass --gc-sections in link line
linux: pass --gc-sections in link line

We have compile flags set up to support using --gc-sections, but apparently
we aren't using it for the actual link?  This has a large difference on
binary size.

Review URL: http://codereview.chromium.org/399048

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@32244 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser