Forking problems on OS X 2.047

[Byron Heads]

When I use fork I am getting a core.thread.ThreadException: Unable to 
load thread state exception.

This is dmd 2.047 on OS X
I am trying to convert a small C application.


module fork;
import  core.sys.posix.unistd,
        std.stdio;

void main() 
{
    auto pid = fork();

    if( pid > 0 ) { 
        writeln( "Parent" );
    } else if( pid == 0 ) { 
        writeln( "Child" );
    } else {
        writeln( "Failed to fork!" );
    }   
}


$ ./fork
Parent
Child
core.thread.ThreadException: Unable to load thread state
----------------
5   fork                                0x00006de9 thread_suspendAll + 85
6   fork                                0x0000aff0 
D2gc3gcx3Gcx11fullcollectMFPvZk + 32
7   fork                                0x0000afbd 
D2gc3gcx3Gcx16fullcollectshellMFZk + 41
8   fork                                0x0000a0a2 
D2gc3gcx2GC18fullCollectNoStackMFZv + 54
9   fork                                0x0000803c gc_term + 44
10  fork                                0x0000cef6 
D2rt6dmain24mainUiPPaZi6runAllMFZv + 90
11  fork                                0x0000cdc6 
D2rt6dmain24mainUiPPaZi7tryExecMFMDFZvZv + 42
12  fork                                0x0000cd54 main + 168
13  fork                                0x00001a85 start + 53

I tried different flags but the output is the same.