Use of #if DEBUG in reent.h

[Freddie Chopin]

Hi!

Maybe it would be ok to change the offending line to:

#if defined(DEBUG) && DEBUG != 0

This way the old behaviour should be retained in most of the cases.
>From what I've read, if you add "-DDEBUG" to GCC flags, it is
equivalent to "-DDEBUG=1". I also think that any undefined macro in a
"#if whatever" statement is considered to be 0, but this is also only a
GCC extensions.

Regards,
FCh