DLLs with Cygwin don't work

[Chris via Digitalmars-d-learn]

The following:

1. created test C-dll in Cygwin (gcc -shared -o hello.dll hello.o)
2. used "implib.exe /s" to create .lib file
3. linked with D program "dmd test.d hello.lib"

Compiles, program starts but begins to hang as soon as it calls 
the C function (which itself is never executed, no "hello world" 
is printed).

Windows 7, 32bit.

In the past it worked flawlessly. Windows 7 had a few updates 
recently and I updated Cygwin (and of course dmd). I noticed this 
behavior in a customized C-library and wanted to rule out it's 
the library (which works perfectly well on Linux). So I wrote a 
simple "hello world" dll, to see what happens. Exact same 
behavior.

Any ideas? Thanks!