* ecoffswap.h: New file for ECOFF swapping functions which differ
only slightly for different targets.
* libecoff.h: Added prototypes for ecoff.c functions.
(ecoff_backend_data): New structure.
(ecoff_tdata): Added backend_data field. Changed external data
pointers to be PTR rather than to a particular struct.
(ecoff_symbol_struct): Moved in from coff-mips.c.
* coff-alpha.c, coff-mips.c: Moved common functions into ecoff.c.
Added ECOFF backend structures. Include ecoffswap.h.
* coff-msym.c: Removed; superseded by ecoffswap.h.
* bfd.c: Include coff/internal.h.
* Makefile.in (BFD_LIBS): Removed coff-mips.o and coff-msym.o.
Added ecoff.o.
(BFD64_BACKENDS): Added coff-alpha.o.
(CFILES): Removed coff-msym.c. Added ecoff.c.
(bfd.o): Added dependency on $(INCDIR)/coff/sym.h.
(coff-mips.o): Added dependency on ecoffswap.h and coff/ecoff.h.
(ecoff.o, coff-alpha.o): New targets.
(coff-msym.o): Removed target.
