Directive OPTION ELF allows to fine-tune the values written to the
ELF header if output format ELF (see -elf or -elf64) is selected. For other output formats,
this option has no effect. The syntax for the directive is:
OPTION ELF:osabi
The only argument <osabi> will be copied to the ELF header field EI_OSABI.
It's a numeric constant, and according to the elf specs some valid values are: