[CMake] implib option for linker on Win32

[Brad King]

dohadwala, moiz wrote:
> I am trying to create a shared library on windows. The cmake project 
> creates the dll, but it does not create the import library. What 
> options/commands should I provide to get the import library to be generated?

You need to put __declspec(dllexport) tags in your source code to tell 
the compiler/linker what symbols to export from the dll.  By default 
nothing is exported.  This is not a CMake issue, it is just standard 
Windows DLL stuff.

-Brad