Changes due to include file renaming:
* xcoffread.c: internalcoff.h ->coff/internal.c,
coff-rs6000.h ->coff/rs6000.h
* mipsread.c: coff-mips.h ->coff/mips.h
* elfread.c: elf-common.h ->elf/common.h
elf-external.h ->elf/external.h,
elf-internal.h ->elf/internal.h
* dwarfread.c dwarf.h ->elf/dwarf.h
* dbxread.c: aout64.h ->aout/aout64.h
stab.gnu.h ->aout/stab_gnu.h
* coffread.c: internalcoff.h ->coff/internal.h
* buildsym.c: stab.gnu.h ->aout/stab_gnu.h
* depend Updated to take the above into account.