Cannot compile freebsd-base-graphics (4c5467a) on FreeBSD 10.2, compiler fails to recognize warning option

[Arto Pekkanen]

Problem occurred after the merge with HEAD at commit 4c5467a. The new 
source tree from HEAD seems to compile some modules with 
-Wno-shift-negative-value -option, which is NOT supported by the 
compiler
of 10.2-RELEASE-p12

Does anyone have any suggestions on how I could get this kernel to 
compile on 10.2-RELEASE?

It would be problematic for me to upgrade my main laptop's OS to FreeBSD 
HEAD just to test this new kernel.

cc --version
FreeBSD clang version 3.4.1 (tags/RELEASE_34/dot1-final 208032) 20140512
Target: x86_64-unknown-freebsd10.2
Thread model: posix

Compiler output follows:

...
===> bxe (all)
cc  -O2 -pipe -Wno-shift-negative-value  -fno-strict-aliasing -Werror 
-D_KERNEL -DKLD_MODULE -nostdinc  
-I/root/freebsd-base-graphics/sys/dev/bxe -DHAVE_KERNEL_OPTION_HEADERS 
-include /usr/obj/root/freebsd-base-graphics/sys/GENERIC/opt_global.h 
-I. -I/root/freebsd-base-graphics/sys -fno-common -g 
-fno-omit-frame-pointer -mno-omit-leaf-frame-pointer 
-I/usr/obj/root/freebsd-base-graphics/sys/GENERIC  -mcmodel=kernel 
-mno-red-zone -mno-mmx -mno-sse -msoft-float  
-fno-asynchronous-unwind-tables -ffreestanding -fwrapv -fstack-protector 
-gdwarf-2 -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  
-Wno-error-tautological-compare -Wno-error-empty-body  
-Wno-error-parentheses-equality -Wno-error-unused-function  
-Wno-error-pointer-sign  -mno-aes -mno-avx  -std=iso9899:1999 -c 
/root/freebsd-base-graphics/sys/dev/bxe/bxe.c -o bxe.o
error: unknown warning option '-Wno-shift-negative-value'; did you mean 
'-Wno-shift-sign-overflow'? [-Werror,-Wunknown-warning-option]
*** Error code 1

Stop.
make[4]: stopped in /root/freebsd-base-graphics/sys/modules/bxe
*** Error code 1

Stop.
make[3]: stopped in /root/freebsd-base-graphics/sys/modules
*** Error code 1

Stop.
make[2]: stopped in /usr/obj/root/freebsd-base-graphics/sys/GENERIC
*** Error code 1

Stop.
make[1]: stopped in /root/freebsd-base-graphics
*** Error code 1

Stop.
make: stopped in /root/freebsd-base-graphics

-- 
Arto Pekkanen