m68k.h: Declare more functions used in macros.

m68k.h: Declare more functions used in macros.

        * m68k.h: Declare more functions used in macros.
        (REG_CLASS_CONTENTS): Completely embrace initializer.
        * m68k.md (adddi3, subdi3): Add abort call to avoid warning
        about returning no value.
        * cse.c (find_best_addr): Declare p and found_better only if
        needed.
        * dbxout.c (dbxout_continue): Define only if DBX_CONTIN_LENGTH > 0.
        * dwarfout.c (string_length_attribute): #if 0 away.
        * function.c (expand_function_end): Define varible blktramp only
        if needed.
        * jump.c (find_insert_position): Define only if !HAVE_cc0.
        * loop.c (combine_givs_p): Define variable tem only if needed.
        * real.c: Comment out unused functions eabs, eround,
        e{24,53,64,113}toasc and eiinfin.

From-SVN: r19998