[Bug bootstrap/102665] ELF-specific configure flags should be rejected on non-ELF platforms

["iains at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102665

--- Comment #5 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to Eric Gallager from comment #4)
> Hm, looking in gcc/configure.ac (where these are defined), it looks like
> there's a bunch of other flags that this bug could apply to, too...

Note that I would try to clarify:

It is my understanding that the purpose of configure is to isolate the end user
from having to know about all the nasty little nooks and crannies of their
target.  As such it is not a "maintainer preference" to avoid end user having
to manipulate many such options but, rather, that if we reach that situation,
then the configure script is not doing its job and needs work.

As far as I understand things the right behaviour of configure is to choose a 
correct default value for each option based on the target.  The way that the
options work it is usually possible to ignore one for a specific target if it
does not apply at all.

Therefore:

1. making sure defaults are correct is valuable

2. perhaps just ignoring ELF-specific options (for Darwin)is useful (you could,
even diagnose that the option has been ignored if the user attempts to set it).

3. As you have noted, there are quite likely more options that
could/should/maybe already are ignored for Darwin.