Policy for removing target support

[Rainer Orth]

I'm currently working on PR ld/33374 where ld on Solaris claims support
for emulations that are actually rejected.  While looking into this, I
noticed quite a few inconsistencies in both bfd/config.bfd and
ld/configure.tgt in that area, together with cleanup opportunities with
the Solaris linker emulations.

While working on this, I noticed that many long obsolete versions of
Solaris are still listed in both files.  However, I wonder if there's
any use in keeping them since I'm almost certain nobody still uses, let
alone tests them.  While I do have Solaris systems back to Solaris 8 if
really need be, I use them only very rarely for digging into history.
In fact, I've removed Solaris support in GCC for all versions before
Solaris 11.4:

OS version		removed from GCC
			release	year

Solaris 7		4.6	2011		64-bit SPARC support
        8		4.8	2013
	9		5	2015
	10		10	2020            64-bit x86 support
	< 11.4		15	2025

As you can see, many have been removed from GCC for more than a decade
and I don't see much use in developers being able to use current
versions of binutils with an ancient version of gcc, if the combination
builds and works at all.

My suggestion would be to remove support for any version before Solaris 10.  
While the code to be removed would not be large (mostly sections in
config.bfd and configure.tgt), we'd be left with only configurations
where the OS is 64-bit capable, so no need to handle 32-bit-only
configs.

However, I wonder what the binutils policy for such removals is.  When I
suggested removing IRIX 5 and 6 and Tru64 UNIX support a couple of years
ago, that met with considerable resistance (especially for IRIX)
although support had been removed from GCC in 4.6 (IRIX < 6.5, Tru64
UNIX V4/V5.0) resp. 4.8 (IRIX 6.5 and Tru64 UNIX V5.1B).

	Rainer

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Rainer Orth, Center for Biotechnology, Bielefeld University