perf beauty: Add a string table generator for renameat2's flags constants

Using the already copied tools/include/uapi/linux/fs.h file:

  $ tools/perf/trace/beauty/rename_flags.sh
  static const char *rename_flags[] = {
	[0 + 1] = "NOREPLACE",
	[1 + 1] = "EXCHANGE",
	[2 + 1] = "WHITEOUT",
  };
  $

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-ta2jbh03spkymp4sbdh489g8@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/trace/beauty/rename_flags.sh

+#!/bin/sh
+# Copyright (C) 2018, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
+# SPDX-License-Identifier: LGPL-2.1
+
+[ $# -eq 1 ] && header_dir=$1 || header_dir=tools/include/uapi/linux/
+
+fs_header=${header_dir}/fs.h
+
+printf "static const char *rename_flags[] = {\n"
+regex='^[[:space:]]*#[[:space:]]*define[[:space:]]+RENAME_([[:alnum:]_]+)[[:space:]]+\(1[[:space:]]*<<[[:space:]]*([[:xdigit:]]+)[[:space:]]*\)[[:space:]]*.*'
+egrep -q $regex ${fs_header} && \
+(egrep $regex ${fs_header} | \
+	sed -r "s/$regex/\2 \1/g"	| \
+	xargs printf "\t[%d + 1] = \"%s\",\n")
+printf "};\n"