a bug regarding when to set the debug version. It waited until both
include and library were set, but it shouldn't wait on include.
Also added a fix to the optional warning flags."
so I' ve set up a macro that uses the variable name expanded for linking, and test if a variable ${LINK_VAR_NAME}_DEBUG
like OPENTHREADS_LIBRARY_DEBUG exists and in case uses it for linking in debug mode.
I' ve also set up FindOpenThreads to set up these variables.
I had to edit the core libraries CMakeLists to add the calls to the macros used.
I' ve tested under MSVC"