FPC 2.6.x should work and even earlier ones.
Could it be possible that you give a source-project-Idea-FPC example
There is no any specific project-like entities. Any .pas (.pp, .lpr) single file can be compiled and ran.
RTL library path is not saved in IDEA project file (.iml) as it's a SDK's setting.
If compiler can't find RTL units the path wasn't added automatically and should be added manually.
Menu File->Project structure->SDKs
Than select a FPC SDK and in source path tab add directory where FPC RTL is located (/usr/lib/codetyphon/fpc/units/<target>)