Can't figure out segfault

[Daniel Murphy]

Assuming you've checked that dlopen isn't returning null, I can't find the 
source of the error in that code, sorry.

Unsolicited advice:

Is there any reason you're manually loading the dll rather than using an 
import library?

A couple of remarks about the rest of the code:

Generally in D the constants would all be:
enum uint IL_BLAH = BLAH;
rather than immutable.

You can specify attributes such as public and immutable in blocks

public immutable
{
   // lots of constants
}

Or if using enums, the following will have the same effect.

enum : uint
{
   constant1 = value,
   constant2 = value,
}


All of your function pointers are currently thread local, as are the static 
ctor/dtors.
To have them run once rather than once per thread, you should use 'shared 
static this()' and 'shared static ~this()' instead, and mark the function 
pointer variables as __gshared.

In all of the 'pointer = cast(function pointer)dlsym(...);' calls you're 
actually relying on a compiler bug, as you're assigning a 'extern(D) 
something function(args)' to a 'extern(System) something function(args)'.

For shorter, clearer and correct code you could instead use:
blah = cast(typeof(blah))dlsym(...);

You don't need to call std.string.toStringz on string literals, they're 
guaranteed to be null-terminated.

All the function signatures using immutable (void 
function(immutable(char)*), etc) are incorrect.  C or C++ function 
signatures should be using const instead (eg void function(const(char)*) ).

I really suggest using an import library if possible.