|But ol' CCS Chokes on:

|#DEFINE OSCCAL 5
|#ASM
|    org 0               <<<<<<<<<<ERROR
|    movwf OSCCAL
|#ENDASM

Does CCS not by default place a MOVWF there for you?  What does it do as
its startup code prior to the first line of main()?

|as well as

|#DEFINE OSCCAL 5
|#ASM
|    movwf OSCCAL        <<<<<<<<<<<ERROR
|#ENDASM

|Any ideas?

#byte OSCCAL=5

And then at the start of main(), if W is intact (probably should be, but
check startup code), do:

        movwf OSCCAL

and you should be fine.