* dwarfout.h, dwarf2out.h, dbxout.h, sdbout.h:  New files.
        Prototypes for externally used functions in respective C files.
        * dwarfout.c, dbxout.c, dwarf2out.c, sdbout.c, toplev,c,
        final.c: Include above files.
        * Makefile.in (toplev.o): Add dependency for above four headers.
        (final.o): Likewise.
        (dwarfout.o, dbxout.o, dwarf2out.o, sdbout.o): Depend on four
        respective header files.

From-SVN: r19835