How to tell Subversion what is the encoding of a file?

[JWalker]

Hi,

I use ViewVC for viewing SVN repositories. I have files (C source
files) with comments written in cyrillic (Windows-1251). ViewVC
display these comments as ? characters. I was told in another forum
that I have to tell Subversion what the encoding of these text files
is, so as Subvewrsion to be able to tell ViewVC this information. So
my question is: How to tell Subversion what the encoding is? May I
have to set some property on the files? What property?

Ivan