[Buildroot] [PATCH 1/1] Fix nconfig for systems with both ncurses and ncursesw

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Hello,

On Sat, 13 Jan 2018 19:12:02 -0800, Guillermo A. Amaral wrote:
> Buildroot's "make ncurses" stopped working a while ago on all my Gentoo

Are you sure it's "make ncurses" that failed ? Or "make nconfig" ?

> systems, running the command would just cause it to crash.
> 
> I look into it and found that the issue was caused by lxdialog's cflags
> which are also used to build nconfig; It would detect *ncursesw* and turn
> on WIDECHAR support -- but the Makefile would still link to plain
> *ncurses* while building nconfig (which was built without WIDECHAR
> support).
> 
> This would cause a crash after using *wattrset* on a WINDOW instance.
> WIDECHAR *wattrset* would try to set the _color member in the WINDOW
> struct which does not exist in the NON-WIDECHAR ncurses instance. It
> would end up clobbering data outside the struct (usually _line entries).
> 
> Just linking to *ncursesw* instead could possibly brick nconfig on older

brick -> break

> systems, so I decided to use the same lxdialog script used to find
> ncurses' cflags/ldflags for menuconfig.
> 
> Signed-off-by: Guillermo A. Amaral <g@maral.me>
> ---
>  support/kconfig/Makefile | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/support/kconfig/Makefile b/support/kconfig/Makefile
> index 7eb4071b4e..f54a60baff 100644
> --- a/support/kconfig/Makefile
> +++ b/support/kconfig/Makefile
> @@ -220,8 +220,10 @@ HOSTCFLAGS_gconf.o	= `pkg-config --cflags gtk+-2.0 gmodule-2.0 libglade-2.0` \
>  HOSTLOADLIBES_mconf   = $(shell $(CONFIG_SHELL) $(check-lxdialog) -ldflags $(HOSTCC))
>  
>  HOSTLOADLIBES_nconf	= $(shell \
> -				pkg-config --libs menu panel ncurses 2>/dev/null \
> -				|| echo "-lmenu -lpanel -lncurses"  )
> +				pkg-config --libs menu panel 2>/dev/null \
> +				|| echo "-lmenu -lpanel")
> +HOSTLOADLIBES_nconf	+= $(shell $(CONFIG_SHELL) $(check-lxdialog) -ldflags)
> +
>  $(obj)/qconf.o: $(obj)/.tmp_qtcheck
>  
>  ifeq ($(qconf-target),1)

Thanks for your patch. I have a few questions:

 - Could you submit it upstream to the Linux kernel?

 - You should also create a patch in support/kconfig/patches/. Indeed,
   we keep a quilt stack of patches on top of the upstream Linux kernel
   kconfig code.

 - Why are you not passing $(HOSTCC) like is done for
   HOSTLOADLIBES_mconf ?

Best regards,

Thomas Petazzoni
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com