* symfile.h (struct sym_fns): Add new field sym_read_linetable.

    * symfile.h (struct sym_fns): Add new field sym_read_linetable.
        * coffread.c, dbxread.c, elfread.c, mipsread.c somread.c:
        Adjust the struct sym_fns object accordingly by setting
        the new field to NULL.
        * xcoffread.c (aix_process_linenos): Make static.
        (xcoff_sym_fns): Set new field to aix_process_linenos.
        * buildsym.c (end_symtab): Replace call to PROCESS_LINENUMBER_HOOK
        by call to new the new sym_fns sym_read_linetable function.
        * config/powerpc/aix.mt (DEPRECATED_TM_FILE): Delete.
        * config/rs6000/tm-rs6000.h: Delete.