* elf.c (prep_headers): Get the machine code from the elf

* elf.c (prep_headers): Get the machine code from the elf
backend data.
* elf-m10200.c (ELF_MACHINE_CODE): Redefine to EM_MN10200.
(ELF_MACHINE_ALT1): Define to EM_CYGNUS_MN10200.
* elf-m10300.c (ELF_MACHINE_CODE): Redefine to EM_MN10300.
(ELF_MACHINE_ALT1): Define to EM_CYGNUS_MN10300.
* elf-arc.c (arc_elf_final_write_processing): Don't override
e_machine, it's now properly set in prep_headers.
* elf32-avr.c (elf32_avr_object_p): Accept both EM_AVR and
EM_AVR_OLD.
(ELF_MACHINE_ALT1): Define to EM_AVR_OLD.
* elf-d10v.c (ELF_MACHINE_CODE): Redefine to EM_D10V.
(ELF_MACHINE_ALT1): Define to EM_CYGNUS_D10V.
* elf-d30v.c (ELF_MACHINE_CODE): Redefine to EM_D30V.
(ELF_MACHINE_ALT1): Define to EM_CYGNUS_D30V.
* elf-fr30.c (ELF_MACHINE_CODE): Redefine to EM_FR30.
(ELF_MACHINE_ALT1): Define to EM_CYGNUS_FR30.
* elf-m32r.c (ELF_MACHINE_CODE): Redefine to EM_M32R.
(ELF_MACHINE_ALT1): Define to EM_CYGNUS_M32R.
* elf32-pj.c (ELF_MACHINE_ALT1): DEfine to EM_PJ_OLD.
* elf-v850.c (ELF_MACHINE_CODE): Redefine to EM_V850.
(ELF_MACHINE_ALT1): Define to EM_CYGNUS_V850.