Tango built as a dynamic library

[Jacob Carlborg]

I've managed to build Tango as a dynamic library with DMD on Mac OS X. I 
had some problems first but I managed to solve them and everything seems 
to work now.

What I had to do to build it as a dynamic library was:

Resolve the undefined symbol _Dmain.

Remove the globals _deh_beg and _deh_end in the deh module and 
_minfo_beg and _minfo_end in the object module. The beg and end 
variables are for determine the beginning and the end of special 
sections in the binaries but they're not put into the dynamic library 
and therefore cause linker errors (undefined symbol).

Get the module infos from the loaded executable and all the loaded 
dynamic libraries and collect them into one array (in the object module) 
in the order they are loaded (the data from executable should be last in 
the array).

Get all the exception handler tables from the loaded executable and all 
the loaded dynamic libraries and collect them into one array (in the deh 
module) in the order they are loaded (the data from executable should be 
last in the array).

Now when I thing about it what happens when a dynamic library built with 
GDC or LDC is linked with an executable built with DMD? I'm searing for 
specific segments and sections in the binaries that at least DMD puts there.

The next step is to clean up the code, create a patch, add support for 
64bit binaries and perhaps universal binaries (if that is needed). Then 
I'll do the same for Phobos 1 and 2.


/Jacob Carlborg