On versions of the PicBasic Pro Compiler earlier than 2.33, Define ONINT_USED 1 was necessary when using the MeLabs boot-loader to keep library code from being inserted in the first 4 locations.

Define LOADER_USED 1 is used for newer versions. You'll receive the error message Opcode Expected Instead of '1' when using the older define with a newer version of PBP.