PATCH] fix-cc-options-test to ensure we do not step on compile flags

[Jory A. Pratt]

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If the tests do not pass the macro of -D__KERNEL__ we overstep compile
flags needed to build a proper kernel. If the check is not correct the
kernel will use -fPIE if gcc specs passes as default options.
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The arch/*/boot/Makefile use cc-options to check for GCC command options and
cc-options use the hardened specs when checking for GCC command options.
When -fPIE is pass to cc1 it can't use -ffreestanding or -fno-toplevel-reorder.
Then it fail to build stuff with -ffreestanding and -fno-toplevel-reorder.
Thanks to Fredric Johansson <johansson_fredric@xxxxxxxxxxx> for finding the main
problem behind a failed build using a hardened toolchain.

Signed-off-by: Magnus Granberg <zorry@xxxxxx>
Signed-off-by: Jory A. Pratt <anarchy@xxxxxxxxxx>

diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index c29be8f..43300b3 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -105,12 +105,12 @@ as-instr = $(call try-run,\
 # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
 
 cc-option = $(call try-run,\
-	$(CC) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",$(1),$(2))
+	$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",$(1),$(2))
 
 # cc-option-yn
 # Usage: flag := $(call cc-option-yn,-march=winchip-c6)
 cc-option-yn = $(call try-run,\
-	$(CC) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",y,n)
+	$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",y,n)
 
 # cc-option-align
 # Prefix align with either -falign or -malign