[Buildroot] [PATCH] linux: don't override HOSTCC for kconfig

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

Hello,

On Thu, 17 May 2018 14:39:21 +0200, Arnout Vandecappelle
(Essensium/Mind) wrote:
> Kconfig uses either pkg-config or hard-coded /usr/include paths to find
> the ncurses or ncursesw library. If ncursesw is found, it will include
> <ncursesw.h>. Since Buildroot's host-ncurses doesn't install a .pc file,
> and linux.mk anyway doesn't pass the pkg-config options to find the host
> pkg-config files, Kconfig will always find the system's ncursesw.h.
> 
> However, since commit dde090c299 (linux: fix passing of host CFLAGS and
> LDFLAGS) HOST_LDFLAGS is passed to the linux build system. Thus, if
> host-ncurses was already built before 'make linux-menuconfig' is called,
> the build will pick up libncurses from the host directory, which is NOT
> widechar. Thus, two different ncurses configurations are mixed into the
> final mconf program. This will result in serious breakage in the
> rendering of the menus (lots of @ and question mark characters).
> 
> As a workaround (suggested by Yann), don't pass HOST_CFLAGS and
> HOST_LDFLAGS when running kconfig commands. For kconfig, we should never
> need host packages anyway. This way, the kconfig calls will always use
> the system's ncurses and never our host-ncurses.
> 
> Note that the same problem could pop up for other kconfig packages as
> well if we ever pass HOST_CFLAGS/HOST_LDFLAGS to them. We could force
> HOSTCC=$(HOSTCC) directly in kconfig-package. However, for now there
> are no other packages that exhibit this problem, so this can be
> revisited when they do.
> 
> Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
> Cc: David De Grave <david.degrave@essensium.com>
> Cc: Scott Fan <fancp2007@gmail.com>
> Cc: Yann E. MORIN <yann.morin.1998@free.fr>
> ---
> v3: override LINUX_KCONFIG_OPTS instead of building host-ncurses with
>     wchar
> ---
>  linux/linux.mk | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)

Applied to master, thanks.

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com