Options such as -omagic or -opt-remarks-* should be interpreted as -o.

Options can start with `-` or `--` unless they start with "o".
Any option that starts with `-o` should be interpreted as an output
file name. This is a quote from the GNU ld man page.

  Note -- there is one exception to this rule.  Multiple letter
  options that start with a lower case 'o' can only be preceded by
  two dashes.  This is to reduce confusion with the -o option.
  So for example -omagic sets the output file name to magic whereas
  --omagic sets the NMAGIC flag on the output.

We didn't handle that properly before.

llvm-svn: 297508