RFA: Port maintainers: Convert WORDSIZE[32|64]/ld to abi-variants

[Joseph S. Myers]

HJ, I don't see how default-abi gets set for powerpc, s390 or sparc - I 
think you're missing appropriate settings in six sysdeps makefiles for 
those.

The setting in Makeconfig

ifdef abi-variants
ifndef default-abi
default-abi = $(firstword $(abi-variants))
endif
endif

isn't going to be effective - Makerules includes $(sysdep-makefiles) 
*after* it includes Makeconfig, so abi-variants won't be set at that 
point.  And it would be wrong for half the ABIs if it was effective.

I see a file "stubs-.h" installed on powerpc because of this.

-- 
Joseph S. Myers
joseph@codesourcery.com