Run Microsoft Analyzer over dmd source code

[Don]

Walter Bright wrote:
> On 8/8/2011 9:44 PM, Don wrote:
>> Aargh, you're right.
> 
> I've been slowly going through the reports. While I've found only one 
> real bug, and several "sort of" problems if you squint at them the right 
> way, most are issues I put in the category of "not up to modern coding 
> best practices". Those I'm working on fixing.

A big issue I've noticed relates to the type of array indices. If it's a 
32 bit compiler and a 32 bit target, I'd go for size_t.
But what about a 32-bit compiler with a 64 bit target? An index could be 
34 bits...