[Darwin] Patch, take 2: enable linkonce support for Darwin

[Matt Austern]

On Feb 2, 2004, at 2:39 PM, Mike Stump wrote:

> On Monday, February 2, 2004, at 11:00 AM, Matt Austern wrote:
>> OK!  As you may have noticed, version 3 of my patch avoids COMMON
>> on all platforms where ONE_ONLY is available.
>
> I can't help but wonder if this results in larger .o files (ls -l type 
> sizes), or slower compiles...  and how big of an effect it is.

Slower compile, I can't think of any reason to wonder that.  Larger .o 
files...  Conceivably it could increase or decrease the size of the .o 
files, but the effect is almost certainly negligible.  The compiler 
currently uses COMMON for C++ vague linkage only in a few pretty rare 
cases.  Changing it from "used in a few corner cases" to "not used" 
isn't a big deal, pretty much by definition.

And, of course, we don't have a choice for Darwin.  The only question 
is whether to make this change for Darwin only or to make it uniformly. 
  Unless there's a compelling reason, I prefer the latter.

			--Matt