How to turn off -Werror for kernel build?

[Ian Lepore]

On Sun, 2015-01-04 at 19:24 +0100, Torfinn Ingolfsen wrote:
> I am trying to build an image for a Samsung Chromebook 2 (model XE503C32, "Peach Pi")[4].
> I am following this[1] wiki page. And I'm using the build script[2] Ian Lepore shared with us last year.
> The build machine runs FreeBSD 9.3-stable:
> tingo at kg-core1$ uname -a
> FreeBSD kg-core1.kg4.no 9.3-STABLE FreeBSD 9.3-STABLE #0 r273918: Fri Oct 31 22:52:44 CET 2014
>      root at kg-core1.kg4.no:/usr/obj/usr/src/sys/GENERIC  amd64
> I am trying to build latest -current (revision 276660).
> Initially, config/make.conf and config/src.conf are empty.
> The kernel config file looks like this:
> tingo at kg-core1$ more config/CB2
> # kernel config file for Chromebook 2 Peach Pi
> 
> include         "CHROMEBOOK-PEACH-PIT"
> ident           CHROMEBOOK-PEACH-PI
> 
> #hints          "CHROMEBOOK-PEACH-PIT.hints"
> 
> options        ROOTDEVNAME=\"ufs:/dev/da0p3\"
> 
> ./mk buildworld works
> ./mk buildkernel fails with this:
> tingo at kg-core1$ ./mk buildkernel
> [... snipped for brevity ...]
> --- trap-v6.o ---
> cc  -c -O -pipe  -g -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes  -Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual  -Wundef -Wno-pointer-sign -fformat-extensions  -Wmissing-include-dirs -fdiagnostics-show-option  -Wno-unknown-pragmas   -nostdinc  -I. -I/zs/tingo/work/chromebook/cb2/src/sys -I/zs/tingo/work/chromebook/cb2/src/sys/contrib/altq -I/zs/tingo/work/chromebook/cb2/src/sys/contrib/libfdt -I/zs/tingo/work/chromebook/cb2/src/sys/gnu/dts/include -D_KERNEL -DHAVE_KERNEL_OPTION_HEADERS -include opt_global.h -march=armv7a -funwind-tables -ffreestanding -gdwarf-2  -fno-common -finline-limit=8000 --param inline-unit-growth=100 --param large-function-growth=1000 -mno-thumb-interwork -std=iso9899:1999 -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes  -Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual  -Wundef -Wno-pointer-sign -fformat-extensions  -Wmissing-include-dirs -fdiagnostics-show-option  -Wno-unknown-pragmas    -Werror  /z!
 s/t
>  ingo/wor
>  k/chromebook/cb2/src/sys/arm/arm/trap-v6.c
> cc1: warnings being treated as errors
> /zs/tingo/work/chromebook/cb2/src/sys/arm/arm/trap-v6.c: In function 'abort_handler':
> /zs/tingo/work/chromebook/cb2/src/sys/arm/arm/trap-v6.c:280: warning: 'rv' may be used uninitialized in this function
> *** [trap-v6.o] Error code 1
> 
> bmake[1]: stopped in /zs/tingo/work/chromebook/cb2/obj/arm.armv6/zs/tingo/work/chromebook/cb2/src/sys/CB2
> 1 error
> 
> bmake[1]: stopped in /zs/tingo/work/chromebook/cb2/obj/arm.armv6/zs/tingo/work/chromebook/cb2/src/sys/CB2
> *** [buildkernel] Error code 2
> 
> bmake: stopped in /zs/tingo/work/chromebook/cb2/src
> 1 error
> 
> bmake: stopped in /zs/tingo/work/chromebook/cb2/src
> *** [buildkernel] Error code 2
> 1 error
>        39.78 real        82.19 user        13.60 sys
> so I try to "fix" it by turning off -Werror for kernel builds. According to this page[3], you can do that either in src.conf or in make.conf.
> I try src.conf first:
> tingo at kg-core1$ more config/src.conf
> # build world without -Werror
> NO_WERROR=
> # build kernel without -Werror
> WERROR=
> (yes, I also tried NO_WERROR, but that didn't help either).
> 
> but warnings are still treated as errors?
> tingo at kg-core1$ ./mk buildkernel
> [...]
> --- trap-v6.o ---
> cc1: warnings being treated as errors
> /zs/tingo/work/chromebook/cb2/src/sys/arm/arm/trap-v6.c: In function 'abort_handler':
> /zs/tingo/work/chromebook/cb2/src/sys/arm/arm/trap-v6.c:280: warning: 'rv' may be used uninitialized in this function
> *** [trap-v6.o] Error code 1
> 
> bmake[1]: stopped in /zs/tingo/work/chromebook/cb2/obj/arm.armv6/zs/tingo/work/chromebook/cb2/src/sys/CB2
> 1 error
> 
> bmake[1]: stopped in /zs/tingo/work/chromebook/cb2/obj/arm.armv6/zs/tingo/work/chromebook/cb2/src/sys/CB2
> *** [buildkernel] Error code 2
> 
> bmake: stopped in /zs/tingo/work/chromebook/cb2/src
> 1 error
> 
> bmake: stopped in /zs/tingo/work/chromebook/cb2/src
> *** [buildkernel] Error code 2
> 1 error
>        38.41 real        82.90 user        13.57 sys
> 
> I also tried it in config/make.conf.
> Any hints?
> 
> 
> References:
> 1) https://wiki.freebsd.org/FreeBSD/arm/Chromebook
> 2) http://lists.freebsd.org/pipermail/freebsd-arm/2014-January/007249.html
> 3) https://wiki.freebsd.org/BuildingFreeBSDWithClang
> 4) http://www.chromium.org/chromium-os/developer-information-for-chrome-os-devices/samsung-chromebook-2

I'm not sure why the WERROR= override didn't work, but there have been
several calls recently to eliminate that warning when building with gcc,
because it just gets the warning wrong way too often (as it's doing in
this case).  So I did that in r276666, it should solve your problem.

-- Ian