You just have messed up your Lazarus installation by adding LCL source paths to the unit paths.
The best way to undo is to re-install Lazarus in a new directory.
Why did you add the LCL source paths? That should not be necessary, if you really added the LCL as dependency to your project. If you wish to recompile the LCL, for example because you have installed a new fpc compiler, use Tools -> Configure Build Lazarus.