[PATCH] [AArch64] Add -mgeneral_regs_only option

[Tim Northover]

> The option means 'only use the general registers', so both fp and neon would be disabled.

Actually, another problem with the implementation of this patch has
just occurred to me: doesn't it prevent the user from even writing FP
or NEON instructions even in inline assembly? That strikes me as a
very bad thing, if so.

Cheers.

Tim.