Fixes a regression from 99fa38809f, which
replaced the kcom.h/stdunk.h versions (which zero memory) with local
implementations (which don't).
Standard C++ does not guarantee that memory is zeroed but several classes
rely on this, in particular for their m_Ref and m_bInitialized members.
Ideally the constructors should be fixed to initialize all required members,
but that task is error-prone so for now we simply restore the previous
behavior.
There is no need to compile our DLLs as shared libraries since we are
managing symbols exports and imports through spec files.
On my system, this reduces the configure-time by a factor of two.
