/usr/include/vmime/platforms/ is in libvmime-dev 0.9.2-5build2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/vmime/platforms/posix/
/usr/include/vmime/platforms/posix/posixChildProcess.hpp
/usr/include/vmime/platforms/posix/posixCriticalSection.hpp
/usr/include/vmime/platforms/posix/posixFile.hpp
/usr/include/vmime/platforms/posix/posixHandler.hpp
/usr/include/vmime/platforms/posix/posixSocket.hpp
/usr/include/vmime/platforms/windows/
/usr/include/vmime/platforms/windows/windowsCodepages.hpp
/usr/include/vmime/platforms/windows/windowsCriticalSection.hpp
/usr/include/vmime/platforms/windows/windowsFile.hpp
/usr/include/vmime/platforms/windows/windowsHandler.hpp
/usr/include/vmime/platforms/windows/windowsSocket.hpp