[CommandLine] Add long option flag for cl::ParseCommandLineOptions . Part 5 of 5
Summary:
If passed, the long option flag makes the CommandLine parser
mimic the behavior or GNU getopt_long. Short options are a single
character prefixed by a single dash, and long options are multiple
characters prefixed by a double dash.
This patch was motivated by the discussion in the following thread:
http://lists.llvm.org/pipermail/llvm-dev/2019-April/131786.html
Reviewed By: MaskRay
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61294
llvm-svn: 360532