Remaining host configuration fragments

[Zack Weinberg <zack at codesourcery dot com>]

With the patch I just posted, there are three remaining host Makefile
fragments and ten host configuration headers.  I'd like to go through
them and discuss their remaining uses.

x-interix sets X_CFLAGS (to -D__INTERIX -D_ALL_SOURCE).  It seems to
me that this should be unnecessary, but I am not familiar enough with
Interix to be sure.

m68k/x-next sets BOOT_LDFLAGS; there is a comment about needing to
make enough room for f771.  This falls into the same category as the
stage1_cflags we need for some machines - should be pushed into
configure or config.gcc.

alpha/x-vms enables building two programs and two .o files which are
not useful except on VMS.  The .o files are necessary when targeting
VMS but apparently cannot be built with GCC.  The programs translate
Unix to VMS options; I'm not sure why this is needed.  We're stuck
with this file for the time being.

The xm-headers have four general categories of things in them.

First, dinking with HOST_WIDE(ST)_INT.  This is done by
alpha/xm-alpha-interix.h, alpha/xm-vms.h, alpha/xm-vms64.h, and
i386/xm-i386-interix.h, and should be unnecessary.  hwint.h in
conjunction with the configure script is supposed to get this right
always.  I would appreciate it if the maintainers of these host
configurations would check what happens if the dinking is removed, and
contact me with detailed descriptions of any failures.

Second, adjusting PATH_SEPARATOR, DIR_SEPARATOR, DIR_SEPARATOR_2, and
HAVE_DOS_BASED_FILE_SYSTEM.  This is done by i386/xm-cygwin.h,
i386/xm-djgpp.h, i386/xm-mingw32.h, and i386/xm-vsta.h.  In canonical
form, all four of these are set as a block.  However, xm-cygwin.h does
not set PATH_SEPARATOR, and xm-vsta.h only sets PATH_SEPARATOR (why?)

I think it would be appropriate to slave the SEPARATOR macros to
HAVE_DOS_BASED_FILE_SYSTEM, and move HDBFS into xm_defines.

Third, setting HOST_OBJECT_SUFFIX and/or HOST_EXECUTABLE_SUFFIX.  This
is done by alpha/xm-vms.h, i386/xm-cygwin.h, i386/xm-djgpp.h,
i386/xm-mingw32.h, and vax/xm-vms.h.  There isn't a better place to
put these than there.

Finally, miscellaneous stuff: alpha/xm-vms.h, i386/xm-djgpp.h,
mips/xm-iris5.h, vax/xm-vms.h.  We're stuck with all of it.  Well,
arguably the irix5 and VAX VMS configurations should be scrapped.

zw