Fixed guard in the lexer header.
Fixed guard in the lexer header.

dfockler/oga,altmetric/oga,altmetric/oga,YorickPeterse/oga,altmetric/oga,altmetric/oga,jeffreybaird/oga,ttasanen/oga,ttasanen/oga,ttasanen/oga,ttasanen/oga,ttasanen/oga,dfockler/oga,YorickPeterse/oga,YorickPeterse/oga,jeffreybaird/oga,dfockler/oga,YorickPeterse/oga,dfockler/oga,jeffreybaird/oga,YorickPeterse/oga,altmetric/oga,jeffreybaird/oga,jeffreybaird/oga,dfockler/oga