Subversion does not support the concept of a $GlobalRev$ keyword. There is a command line tool called svnversion that will output revisions to stdout. You can combine that with a script to write this to a file. This is asked about all the time, so there is a FAQ:
http://subversion.tigris.org/faq.html#version-value-in-source
If you are on Windows, there is also a command line program available called SubWCRev.exe that is similar to svnversion but will do substitution in a file for you. Note that you cannot use this on a versioned file, you need the combine it with a template file of some kind. See:
http://tortoisesvn.net/docs/release/TortoiseSVN_en/tsvn-subwcrev.html
Either of these could be run from Eclipse by setting up an External Tool command for it.