Options: Add new option kind that consumes remaining arguments

This adds KIND_REMAINING_ARGS, a class of options that consume
all remaining arguments on the command line.

This will be used to support /link in clang-cl, which is used
to forward all remaining arguments to the linker.

It also allows us to remove the hard-coded handling of "--",
allowing clients (clang and lld) to implement that functionality
themselves with this new option class.

Differential Revision: http://llvm-reviews.chandlerc.com/D1387

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188314 91177308-0d34-0410-b5e6-96231b3b80d8
DAG: Combine (and (setne X, 0), (setne X, -1)) -> (setuge (add X, 1), 2)

A common idiom is to use zero and all-ones as sentinal values and to
check for both in a single conditional ("x != 0 && x != (unsigned)-1").
That generates code, for i32, like:
  testl %edi, %edi
  setne %al
  cmpl  $-1, %edi
  setne %cl
  andb  %al, %cl

With this transform, we generate the simpler:
  incl  %edi
  cmpl  $1, %edi
  seta  %al

Similar improvements for other integer sizes and on other platforms. In
general, combining the two setcc instructions into one is better.

rdar://14689217

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188315 91177308-0d34-0410-b5e6-96231b3b80d8