Add missing defines ...


git-svn-id: svn+ssh://svn.code.sf.net/p/mingw-w64/code/trunk@6480 4407c894-4637-0410-b4f5-ada5f102cad1
Add some code to clarify state of busy and avoid possible underflow of it.


git-svn-id: svn+ssh://svn.code.sf.net/p/mingw-w64/code/trunk@6481 4407c894-4637-0410-b4f5-ada5f102cad1
Destroy mutex in locked-state ... this avoids races on destruction.
Additionally make sure that internal global_lock is released at very end


git-svn-id: svn+ssh://svn.code.sf.net/p/mingw-w64/code/trunk@6482 4407c894-4637-0410-b4f5-ada5f102cad1
Re-add check for busy on mutex-destroy, additional take care that in error-case we try to unlock mutex again.


git-svn-id: svn+ssh://svn.code.sf.net/p/mingw-w64/code/trunk@6483 4407c894-4637-0410-b4f5-ada5f102cad1