Documentation request for -ansi

[Joe Buck]

> I don't propose changing GCC (or libc, for that matter); I
> propose thinking about a way of preventing GCC users who
> use functions like erfc, erf, etc. from the pitfalls of
> using the -ansi switch.

But since there are already flags that protect the user from
this problem, why are you proposing to change -ansi?  This was
why I assumed you weren't aware of existing options.

I suggested -Wstrict-prototypes, which is not included in -Wall.
I should have suggested relying on -Wimplicit, which is included
in -Wall.

Since anyone saying -ansi -Wall will be alerted about the problems
with erf, erfc etc, I don't think there's a problem.  If you have
a user complaining of strange behavior from a program compiled with
GCC, you can ask them whether -Wall is reporting any warnings.