Re: Environment variable to turn off carets

[Alfred M. Szmidt]

   address@hidden @code{NO_CARET_OUTPUT}, environment variable
   +If you want to indicate error positions with a caret (e.g., GCC's
   address@hidden option), you should suppress this
   +indication if the environment variable @code{NO_CARET_OUTPUT} is
   +defined (even if it is defined with a null value).

These things come to my mind,

 1) no program today supports this variable.

 2) all programs that have ADA like caret error messages need to be
    updated.

 3) I don't think there is any precedence to use environment variables
    to change the output in this manner.

It would be far easier to, I think, in the long run specially, to
amend the behaviour of -fxxx type of options where they would produce
a warning instead of a hard error.  There is already precedence with
auotoconf's --with/--without and --enable/--disable options being
silently ignored in older versions, and in newer where they produce a
warning message.  But this is alot of work, and can break old
behaviour.

To have different behaviour between compilation runs, I would
recommend creating a config.site file that one uses whith the specific
settings.  In which you can pass the correct flag to the respective
programs.  This has the benefit that for the programs that do have ADA
caret output, but do not support this environment variable, you can
still silence it.