[crosstool-ng/crosstool-ng] 59b08f: Sync kconfig files with upstream 4.15

  Branch: refs/heads/update_kconfig_4_15
  Home:   https://github.com/crosstool-ng/crosstool-ng
  Commit: 59b08f8d06700770cf1105269acb2ec2460e2a34
      https://github.com/crosstool-ng/crosstool-ng/commit/59b08f8d06700770cf1105269acb2ec2460e2a34
  Author: Bryan Hundven <[email protected]>
  Date:   2018-01-31 (Wed, 31 Jan 2018)

  Changed paths:
    M kconfig/.gitignore
    M kconfig/Makefile.in
    M kconfig/check.sh
    M kconfig/conf.c
    M kconfig/expr.c
    M kconfig/expr.h
    A kconfig/kconf_id.c
    M kconfig/list.h
    M kconfig/lkc.h
    M kconfig/lkc_proto.h
    M kconfig/lxdialog/check-lxdialog.sh
    M kconfig/menu.c
    M kconfig/nconf.c
    M kconfig/nconf.gui.c
    M kconfig/symbol.c
    R kconfig/zconf.gperf
    M kconfig/zconf.y

  Log Message:
  -----------
  Sync kconfig files with upstream 4.15

Last updated with 4.9-rc7.
This commit introduces the following upstream changes:

9059a3493efe kconfig: fix relational operators for bool and tristate symbols
88127dae6ed9 kconfig/symbol.c: use correct pointer type argument for sizeof
b24413180f56 License cleanup: add SPDX GPL-2.0 license identifier to files with no license
bb3290d91695 Remove gperf usage from toolchain
ad8181060788 kconfig: fix sparse warnings in nconfig
ff85a1a80e00 kconfig: Check for libncurses before menuconfig
9be3213b14d4 gconfig: remove misleading parentheses around a condition
83c3a1bad224 xconfig: fix missing suboption and help panels on first run
e039303ff71a xconfig: fix 'Show Debug' functionality
79e51b5c2dee kconfig/nconf: Fix hang when editing symbol with a long prompt
0eb47346968f Scripts: kconfig: nconf: fix _GNU_SOURCE redefined warning
237e3ad0f195 Kconfig: Introduce the "imply" keyword

Signed-off-by: Bryan Hundven <[email protected]>