Add gflags dependency

third_party/gflags/gen/win/include/gflags/gflags_completions.h

Index: third_party/gflags/gen/win/include/gflags/gflags_completions.h
diff --git a/third_party/gflags/gen/win/include/gflags/gflags_completions.h b/third_party/gflags/gen/win/include/gflags/gflags_completions.h
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+// Copyright (c) 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// ---
+// Author: Dave Nicponski
+//
+// Implement helpful bash-style command line flag completions
+//
+// ** Functional API:
+// HandleCommandLineCompletions() should be called early during
+// program startup, but after command line flag code has been
+// initialized, such as the beginning of HandleCommandLineHelpFlags().
+// It checks the value of the flag --tab_completion_word.  If this
+// flag is empty, nothing happens here.  If it contains a string,
+// however, then HandleCommandLineCompletions() will hijack the
+// process, attempting to identify the intention behind this
+// completion.  Regardless of the outcome of this deduction, the
+// process will be terminated, similar to --helpshort flag
+// handling.
+//
+// ** Overview of Bash completions:
+// Bash can be told to programatically determine completions for the
+// current 'cursor word'.  It does this by (in this case) invoking a
+// command with some additional arguments identifying the command
+// being executed, the word being completed, and the previous word
+// (if any).  Bash then expects a sequence of output lines to be
+// printed to stdout.  If these lines all contain a common prefix
+// longer than the cursor word, bash will replace the cursor word
+// with that common prefix, and display nothing.  If there isn't such
+// a common prefix, bash will display the lines in pages using 'more'.
+//
+// ** Strategy taken for command line completions:
+// If we can deduce either the exact flag intended, or a common flag
+// prefix, we'll output exactly that.  Otherwise, if information
+// must be displayed to the user, we'll take the opportunity to add
+// some helpful information beyond just the flag name (specifically,
+// we'll include the default flag value and as much of the flag's
+// description as can fit on a single terminal line width, as specified
+// by the flag --tab_completion_columns).  Furthermore, we'll try to
+// make bash order the output such that the most useful or relevent
+// flags are the most likely to be shown at the top.
+//
+// ** Additional features:
+// To assist in finding that one really useful flag, substring matching
+// was implemented.  Before pressing a <TAB> to get completion for the
+// current word, you can append one or more '?' to the flag to do
+// substring matching.  Here's the semantics:
+//   --foo<TAB>     Show me all flags with names prefixed by 'foo'
+//   --foo?<TAB>    Show me all flags with 'foo' somewhere in the name
+//   --foo??<TAB>   Same as prior case, but also search in module
+//                  definition path for 'foo'
+//   --foo???<TAB>  Same as prior case, but also search in flag
+//                  descriptions for 'foo'
+// Finally, we'll trim the output to a relatively small number of
+// flags to keep bash quiet about the verbosity of output.  If one
+// really wanted to see all possible matches, appending a '+' to the
+// search word will force the exhaustive list of matches to be printed.
+//
+// ** How to have bash accept completions from a binary:
+// Bash requires that it be informed about each command that programmatic
+// completion should be enabled for.  Example addition to a .bashrc
+// file would be (your path to gflags_completions.sh file may differ):
+
+/*
+$ complete -o bashdefault -o default -o nospace -C                        \
+ '/usr/local/bin/gflags_completions.sh --tab_completion_columns $COLUMNS' \
+  time  env  binary_name  another_binary  [...]
+*/
+
+// This would allow the following to work:
+//   $ /path/to/binary_name --vmodule<TAB>
+// Or:
+//   $ ./bin/path/another_binary --gfs_u<TAB>
+// (etc)
+//
+// Sadly, it appears that bash gives no easy way to force this behavior for
+// all commands.  That's where the "time" in the above example comes in.
+// If you haven't specifically added a command to the list of completion
+// supported commands, you can still get completions by prefixing the
+// entire command with "env".
+//   $ env /some/brand/new/binary --vmod<TAB>
+// Assuming that "binary" is a newly compiled binary, this should still
+// produce the expected completion output.
+
+
+#ifndef GOOGLE_GFLAGS_COMPLETIONS_H_
+#define GOOGLE_GFLAGS_COMPLETIONS_H_
+
+// Annoying stuff for windows -- makes sure clients can import these functions
+#ifndef GFLAGS_DLL_DECL
+# ifdef _WIN32
+#   define GFLAGS_DLL_DECL  __declspec(dllimport)
+# else
+#   define GFLAGS_DLL_DECL
+# endif
+#endif
+
+namespace google {
+
+GFLAGS_DLL_DECL void HandleCommandLineCompletions(void);
+
+}
+
+#endif  // GOOGLE_GFLAGS_COMPLETIONS_H_