struct field alignment

[Walter Bright]

Robert Jacques wrote:
> Although I have a solution that works well for me, the one thing I 
> lament about not having a canonical D way of expression 
> align(8)/align(16), even at only a meta-information level, is that if 
> phobos gets a small vector library, I can't use it and conversely I'm 
> not motivated to improve/submit my own small vector library to phobos.

I'm painfully aware that align(8)/(16) don't work on the 32 bit targets. I've 
been reluctant to fix that because it involves some performance degradation 
(keeping the stack so aligned requires the insertion of stack adjustment 
instructions here and there).

With the 64 bit target, however, the C ABI will force the issue. It'll support 
those alignments.