[WIN32] Fix missed creation of lv2 directory.
This patch fixes issue 200:
https://sourceforge.net/p/zynaddsubfx/bugs/200/
The explanation of the defect is described into this page:
https://cmake.org/cmake/help/v3.9/manual/cmake-buildsystem.7.html
In short:
- All versions of Windows are "DLL platforms", and DLL are targets for "bin" directory.
- On all other "non-DLL platforms", the shared libraries are targets for "lib" directory.
This means that:
- On DLL platforms: RUNTIME_OUTPUT_DIRECTORY and RUNTIME_OUTPUT_NAME target properties are used.
- On non-DLL platforms: LIBRARY_OUTPUT_DIRECTORY and LIBRARY_OUTPUT_NAME target properties are used.
So, RUNTIME_OUTPUT_DIRECTORY must be set in addition to LIBRARY_OUTPUT_DIRECTORY for supporting "DLL platforms".