Re: Appending to config.log

[Akim Demaille]

| > Do we know that file descriptor 5 will always be sent to config.log?
| > That's not documented anywhere, so I don't know that we can count on
| > it.  I think what really need here is a documented macro supplied by
| > autoconf that allows us to use the appropriate file descriptor, no
| > matter what it is.

Such an FD is too low level a detail to be left to the user.  We try
to publish high level interface, and keep low level private to
Autoconf, so that we can adjust Autoconf to future needs.
 
| (been there/done that/been ignored - 1997):
| 
| dnl Write a debug message to config.log, along with the line number in the
| dnl configure script.
| AC_DEFUN([CF_MSG_LOG],[
| echo "(line __oline__) testing $* ..." 1>&AC_FD_CC
| ])dnl

The internal detail AC_FD_CC no longer exists, and is replaced with
the internal detail AS_MESSAGE_LOG_FD.  As an internal detail, an
internal AU_ALIAS preserve some backward compatibility with the
internal detail AC_FD_CC.