Syntax: bf(%locationstruct) tt(struct-definition) nl() 
           Defines the organization of the location-struct data type
            bf(LTYPE__). This struct should be specified analogously to the
            way the parser's stacktype is defined using bf(%union) (see
            below). The location struct type is named bf(LTYPE__). If neither
            bf(locationstruct) nor bf(LTYPE__) is specified, the
            default link(LTYPE__)(LSPNEEDED) struct is used.
