[doc patch]: Clarify portability

[Joseph S. Myers]

On Mon, 14 Oct 2002, Nathan Sidwell wrote:

> ! GCC itself aims to be portable to any machine where 'int' is at least
> ! a 32-bit type. It aims to target machines with a flat (non-segmented) byte
> ! addressed address space. Target ABIs may have 8, 16, 32 or 64 bit 'int'
> ! type.

That should be @code{int}.  Though some targets may have 8-bit int, that
is a nonconforming mode.  I don't know to what extent changes are needed
to support the 36-bit int in the PDP-10 port.  "64-bit" is hyphenated as
an adjective.  Also note that target char wider than 8 bits is supported
(e.g. c4x) but may have some problems in some cases: not all the compiler
properly allows for target chars different from host chars although the
target macros support it (and even support target char wider than target
hardware byte, support which is used by no target).

-- 
Joseph S. Myers
jsm28@cam.ac.uk