Difference in dmd and gdmd -lib option

[Dan Olson]

I am coming back to D fun after a year.  I am playing on osx 10.6 and just
built native gdc last weekend using github gdc-4.7.

Sorry if this has been discussed before, but my searches could not find
it.  I discovered that dmd and gdmd -lib behave different. I really like
the way dmd -lib option works.  Is this known, expected, or something
that should be fixed?

dmd -lib breaks up a d module (file) into separate compilation units so,
for example, if a d module has 5 funtions, the library will have 5 or
more .o (one for each function).  If you link to only one of those
functions, you only get it in your final executable.

gdmd does not.  It produces a single .o per d module

The beauty of the dmd approach is that I can call D code from an objc
program, and only the parts of the dmain2.d needed are linked in
(rt_init/rt_term).  With gdc, I can't get rt_init() and rt_term()
without also getting the dmain2's extern(C) main().

So I am forced to have D be main.  Or I must go in and break up dmain2.d
into smaller code pieces if I want to have D libs callable by objc.

I am switching to gdc because "I have a Dream" that one day D can be
used to write ios apps.  And gdc has the arm ISA so I can cross-compile.
So it is closer than dmd.  I know eventually it will need a rewritten
druntime, but my baby step is to just compile a D function and call it
from an ios app.  But even tinier step I am on now is to call a D
function from iphone sim (which uses i386).

Thanks and many adventures,
Dan