[Cmake] Buffer overflows

[Brad King]

> I'm not sure that reading character-by-character, especially using the
> stream iterators, is any less efficient. There isn't (shouldn't be) a 
> disk access per iterator dereference, since these are buffered
> streams, and copying from one stream's buffer directly to the other
> stream's buffer seems more efficient that reading into a temporary 
> buffer first. However, this does imply doing things like
> fin.setf(ios::skipws), or, according to the standard,   
> fin.setf(ios_base::skipws). Maybe it's best to avoid such issues.
I doubt the compiler will generate code from that std::copy with iterators
that runs as fast as the pre-compiled (assembly?) implementation of the   
standard library's getline.

> Anyway, I guess the simplest solution is just to check for fin.fail()
> after the readline, and reset the flag if it does happen.
I have just checked in code that uses an approach like this.  I had
written it this morning, but cmake's repository has been broken for a few
hours so I couldn't compile and test it until just now.  The new code can
copy any file even with a 2 byte buffer.

-Brad