And unistd.h is not available on windows.
`UuidCreate`, `UuidToString` and `RpcStringFree` need special library on windows. Lets not use them.
The `common` name is from the time where kiwix was only one repository for all the project (android, desktop, server...). Now we have split the repositories and kiwix-lib is the "common" repo, the "common" directory is somehow nonsense.