[patch] change specific int128 -> generic intN

[Joseph S. Myers]

The changes to dwarf2asm.c, cppbuiltin.c, optabs.c, defaults.h, expr.c, 
expmed.c, tree-dfa.c, simplify-rtx.c, lto-object.c, loop-iv.c, varasm.c, 
the msp430 back end and some of the stor-layout.c changes don't look like 
they should depend on the rest of the patch.  I think it would help review 
if anything that can reasonably be separated from the main intN support is 
posted separately, as a much smaller patch with its own self-contained 
rationale (I presume all those changes should work fine without the main 
intN support), and then the intN patch only contains things directly 
related to intN support.

-- 
Joseph S. Myers
joseph@codesourcery.com