[Bug driver/63837] [5 Regression] r217391 causes kernel build errors with GCC_COMPARE_DEBUG=1

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63837

--- Comment #9 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #8)
> I bet this is really the same as bug 63881.  The kernel is using /dev/null
> for both the input and output when testing if the options work.

No. From scripts/Kbuild.include:

126 # cc-disable-warning                                                        
127 # Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)     
128 cc-disable-warning = $(call try-run,\                                       
129         $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -x c
/dev/null -o "$$TMP",-Wno-$(strip $(1)))