if -D__KERNEL__ is not passed via KBUILD_CFLAGS the compiler can have 
options passed by default that will unset
other options such as -ffreestanding or -fno-toplevel-reorder if the 
compiler is passing -fPIE.

refer to fix-fpie-from-being-used.diff

Another option that was suggested from another user was to pass 
-D__KERNEL__ via Kbuild.include, patch is also attached.
either patch would work, There is no risk of breakage, benefit is for 
those who use a hardened toolchain.

fix-cc-options-check.patch

I believe we should pass the option via KBUILD_CFLAGS as to not confuse 
the fact that we are not building CPP code, but rather C code.

Also correct me if I am wrong but last I knew only part of kernel that 
was cpp was qconfig.

-Jory