Obsolete config files

[Zack Weinberg]

I believe these config files are obsolete.  They are not mentioned in
config.gcc, or are mentioned only in conjunction with other config
files which do not exist anymore:

1750a/xm-1750a.h
alpha/win-nt.h
alpha/xm-winnt.h
alpha/config-nt.sed
i386/os2.h
i386/xm-os2.h
i386/config-nt.sed
m68k/x-alloca-c
m88k/x-dguxbcs
mips/x-netbsd
mips/x-nws3250v4
rs6000/t-xrs6000
rs6000/x-cygwin

In addition, these config files are mentioned in config.gcc, but do
not exist:

alpha/t-pe
i386/t-go32
m68k/x-hp3bsd44
m68k/x-m68kv
pa/t-openbsd
rs6000/t-openbsd
rs6000/x-aix41-gld
t-osf
winnt/x-winnt

and these config files are empty except for comments:

x-linux-aout
xm-freebsd.h
i386/beos-pe.h
ns32k/xm-netbsd.h

I will submit a patch which removes all of the obsolete or empty files
and all references to nonexistent or empty files.  I'd appreciate if
someone could confirm that the files listed as obsolete are genuinely
so.

zw