RTOS/EK-TM4C1294XL: Compiler Error when trying to build the project

The error is because the linker was unable to find the RTS (run time support) library associated with the version of compiler you were using. You can check the file search path the linker  uses by right clicking on the project name in the "Project Explorer" window of Code Composer Studio and selecting "Show Build Settings". Then navigate to the "CCS Build" -> "ARM Linker" -> "File Search Path" level. 

In the example above from my machine, it includes the library libc.a and the search path "${CG_TOOL_ROOT}/lib". This macro expands to "C:\ti\ccsv8\tools\compiler\ti-cgt-arm_18.1.5.LTS\lib" on my machine. Depending on how the project you are using was originally setup, it may be using a path with a hard-coded tool version number that does not match the compiler version you are using.