Fix test DLL export
Fix test DLL export

Fixes issue 16.

Patch by Nathan Rajlich <nathan@tootallnate.net>

dlfcn-win32/dlfcn-win32,dlfcn-win32/dlfcn-win32,gypified/dlfcn-win32,gypified/dlfcn-win32,iamyuiwong/dlfcn-win32