bootstrap/5149: gcc-20011217 reads beyond EOF on cygwin

[Neil Booth]

Christopher Faylor wrote:-

> Can I ask why we'd be reading beyond EOF?  Is it guaranteed that bytes beyond
> EOF will be zero on UNIX?

This was discussed in September (see thread in gcc@ entitled "Bumming
cycles out of parse_identifier").  It was decided that all known
current Unix implementations have zeros until the next page boundary.
Assuming EOF is indicated by a NUL is used as a lexer optimization.

Neil.