The $Id$ keywords were used in Subversion where they can be substituted
with filename, last revision number change, last changed date, and last
user who changed it.
In Git this functionality is different and can be done with Git attribute
ident. These need to be defined manually for each file in the
.gitattributes file and are afterwards replaced with 40-character
hexadecimal blob object name which is based only on the particular file
contents.
This patch simplifies handling of $Id$ keywords by removing them since
they are not used anymore.
This turned out to be rather inconvenient after all. Instead just
return the same output we did on PHP 5. If people want to have an
error, use TOKEN_PARSE.
Primarily to avoid getting fatal errors from token_get_all().
Implemented using a magic E_ERROR token, which the lexer emits to
force a parser failure.
Peter Kokot